Thiết kế bài giảng vật lí 12 nâng cao (tập 2) phần 2

- Khi chidu chum sang cd budc sdng ngdn vao catdt thi hien tupng quang dien ngoai xay ra, trong td bao quang dipn xudt hien cac aiectron quang dian.. GV gidi thiau ba dinh luat quang die

CHL/ONG VH Ll/pNG TLf ANH SANG

BAI43

HlfiN TI/CfNG QUANG D I £ N N G O A I

c A c DINH LUAT Q U A N G DifiN

I - M U C T l £ u

1 Vi kie'n thflc

- Hieu va nhd dupe eac khai niem: hian tupng quang dipn, aiectron quang dian, ddng quang didn, gidi ban quang dipn, ddng quang dian bao hoa, hiau dian thd ham

- Hidu dupe npi dung va nhan xet ka't qua thi nghiam khao sat dinh lupng hian tupng quang dien

- Hidu va phat tridn dupe edc dinh luat quang dian

2, Vi ki nSng

- Ren luyan ki nang giai thieh cae hipn tupng vat li

- Ren luyan ki nang phan tich ka't qua thi nghiem

II - CHUXN BI

Gido vien

- Ve hinh 43.1,43.2,43.3 va 43.4 SGK tran gia'y khd AQ

Hoc sinh

- 6n lai cac kidn thflc vd cdng eua lye dian trudng, dinh 11 dpng nang, khai niam \

cudng dp ddng dien bao hoa

m - THifiT K£ H O A T D 6 N G D A Y HOC

Hoat ddng cua hoc sinh Trp giup cua giao vi§n

Hoat ddng 1

Kidm tra, chuan bj dieu kien

xua't phat Dat van de

HS suy nghl ca nhan tim cau tra ldi

- Khi catdt bi ddt ndng, cae

electron ty do trong kim loai nhan

dupe nang lupng edn thiet dd bflt ra

khdi mat catdt Do dd, trong dng

chan khdng cae electron ty do

chuydn dpng hdn loan Khi khoa

K2 ddng, andt dupe ndi vdi cue

ducfng, catdt dupe ndi vdi eye am

cua ngudn dian thi eac electron se

chuyen dpng tfl catdt sang andt tao

ra ddng dipn Khi do sd chi cua

miliampe ke khae khdng

GV nau cau hdi kiem tra kidn thflc cu

- Lam thi nghiem vdi didt chan khong theo so dd sau :

Ddt ndng catdt bang ngudn dian ^i, sau

dd md K], ddng K2 thi miliampe kd chi the nao ? Tai sao ?

- Khao sat sy phu thupc cua cudng dp ddng dian trong chan khdng vao hipu dien the U dat gifla andt va catdt ngudi

ta thu dupe dudng dac tuydn vdn-ampe

I

O

- Cudng dp ddng dian khi dd dat

gia tri bao hoa

Nhan xet gi vd cudng dp ddng dian khi

- Do tia tfl ngoai chieu vao tdm

kem nan lam cho aiectron bi bat ra

khdi ta'm kem Khi dung tam thuy

tinh khdng mau chan chum tia tfl

ngoai thi khdng hai la dien nghiem

khdng bj khep lai vi ta'm thuy tinh

da hdp thu hdu het eac tia tfl ngoai

HS tiep thu, ghi nhd

GV md ta thi nghiam phat hian hian tupng quang dian do nha vat li ngudi Dfle, Hee da lam, yau cdu HS ldng nghe

va tra ldi cac cau hdi dd tim hidu hian tupng quang dien ngoai

t

- Chieu anh s ^ g uu qud7!| vao mpt tdm kem P ban ddu tich dien am thi hai la eua dian nghiem khep lai

- Chdn chum tia hd quang bang tdm thuy tinh khdng mau thi hai la eua dian nghiem khdng bi khep lai

Giai thich tai sao ?

GV thong bao

- Hian tupng anh sang lam bat eac aiectron ra khdi bd mat kim loai gpi la hian tupng quang dien ngoai, thudng gpi tat la hien tupng quang dien

- Cac eletron bj bat ra khdi bd mat kim loai bj chieu sang gpi la quang aiectron, hay cdn gpi la aiectron quang dien

Hoat ddng 3

Tim hieu thi nghiam khao sat

dinh lupng hien tupng quang

dien

HS chu y ldng nghe va quan sat

hinh ve te bao quang dian tran gidy

khoAo

- Khi chidu chum sang cd budc

sdng ngdn vao catdt thi hien tupng

quang dien ngoai xay ra, trong td

bao quang dipn xudt hien cac

aiectron quang dian Dudi tac dung

ciaa lye dian trudng, cae aiectron

GV gidi thiau te bao quang dien trong thi nghiem khao sat djnh lupng

- Td bao quang dien la mpt binh bang thach anh da hut hdt khdng khi, ban trong cd hai dien eye: andt la mpt vdng day kim loai; catdt cd dang mpt chdm cdu bang kim loai ma ta edn khao sat

GV md ta thi nghiam vdi td bao quang dien, yau cdu HS tra ldi cac cau hdi dd tim hieu thi nghiem khao sat dinh lupng hian tupng quang dipn

- Ddng khoa C va di chuyen con chay B

dd U^i^ >0 Chia'u chum sang cd budc sdng ngan vao catdt thi hipn tupng gi xay ra ? Nhan xet gi ve sd ehi cua dien kdG?

quang dien chuyen dpng tfl catdt

sang andt tao thanh ddng dien chay

trong mach Kim dien kd G Ipch

khdi vi tri 0

- Didu kian dd xay ra hien tupng

quang dipn la anh sang chieu tdi

ban kim loai cd budc sdng phai

nhd hon hoac bang mpt gia tri

XQ nao dd

- Dudng dac tuydn von-ampe

khdng phai la dudng thdng nan

cudng dp ddng dien trong td bao

quang dien khdng tuan theo dinh

luat 6m

- Khi U^K > Uj, cudng dp ddng

dian gifl gia tri khdng ddi I =

Ibh Khi U^j^ < Ibh Uh thi ddng quang

dian bi triat tiau hoan toan (I = 0)

- Dung cac kinh loc sac F khae nhau thi thdy ddng quang didn chi xudt hian khi anh sang chidu vao catdt cd budc

sdng nhd hon hoac bang tri sd XQ

Vay, didu kian de xay ra hiph tupng quang dipn la gi ?

- Vdi mpt chum sang don sdc ed budc sdng X<XQ va cd cudng dp sang nhdt dinh thi sy phu thupc eua cudng dp ddng quang dien I vao hieu dian thd

cd gia tri bang khdng khi nao ?

- Cudng dp ddng I^h ti la thuan

vdi cudng do anh sang

- Gifl nguyan tri sd cua budc sdng X,

tang cudng dp sang chieu vao catdt va

ve dupe dudng dac tuydn thfl 2 Nhan xet gi vd sy phu thupc cua ddng If,,, vao cudng dp chum sang ?

GV bd sung kidn thflc

- Khi U^K -"^h thi ddng quang dipn

hi triat tiau hoan toan vi: aiectrwi bj bat

ra tfl catdt, vdi tde dp ban ddu VQ^^^^ va dpng nang ban ddu, da chiu tac dung eua lye dipn trucmg hudng vd catdt; lye nay da ngan khdng cho aiectron tdi andt

dd gay ra ddng quang dian Vi vay,

Uh dupe gpi la hipu dipn thd ham Tri sd

cua Uf, phu thupc budc sdng X Nhu

vdy, gifla dpng nang ban ddu cue dai cua aiectron va dp ldn cua hieu dian thd ham cd hp thflc :

xiT ^^Omax - pTT

"^dmax - 2 ~ '^

- Ddng dian I^h gpi Id cudng dp ddng quang dian bao hoa

GV gidi thiau ba dinh luat quang dien

~ Dinh luat vd gidi han quang dian: Hien tupng quang dian chi xay ra khi anh sang kieh thich chidu vao kim loai

cd budc sdng nhd hon hoac bang budc

sdng XQ, XQ duac gpi la gidi ban quang dian cua kim loai dd : XQ< X

HS chu y ldng nghe va ghi nhd

HS thao luan ehung toan ldp

- Dinh luat quang dien thfl nha't

dupe rut ra tfl ket qua thi nghiem

ddu tian : Didu kian dd xay ra hien

tupng quang dian la anh sang

chia'u tdi ban kim loai ed budc

sdng phai nhd hon hoac bang mpt

gia trj XQ nao dd

- Dya vao dudng dac trung

vdn-ampe ta tha'y ddng quang dien bao

hoa ti la thuan vdi cudng dp chum

sang kich thieh Ke't qua thi

nghiam nay eho phep ta suy ra

dinh luat quang dien thfl hai

- Theo ka't qua thi nghiem tran ta

tha'y: Trj sd cua U,, phu thupc

budc sdng X

Mat khae W, dmax _ " I X O m a x _ = eU„

va vdi mdi kim loai thi cd mpt gidi

ban quang dien nhat djnh nan ta

suy ra dinh luat quang dian thfl 3

- Dinh luat ve cudng dp ddng quang dien bao hoa : Ddi vdi mdi anh sang thich hpp (cd ^o - ^ ) ' cudng dp ddng quang dien bao hoa ti le thuan vdi cudng dp cua chum sang kieh thieh

- Dinh luat vd dpng nang eye dai cua quang aiectron : Dpng n ^ g ban ddu eye dai eua quang aiectron khong phu thupc vao cudng dp eua chum sang kieh thich,

md ehi phu thupc budc sdng anh sang kich thieh va ban ehdt cua kim loai

GV yau cdu HS tra ldi eau hdi sau de tim hieu eac djnh luat quang dien

- Cac djnh luat quang dipn tran dupe rut

ra tfl ket qua thi nghipm nao ?

Hoat ddng 5

Cung cd bai hpc va dinh hudng

nhiem vu hpc tap tiep theo GV nau cau hdi cung c6 bai hpc

- Hay chflng td ring, ba djnh luat quang dien bao ham dupe tat ca kdt qua thi nghiem tran

- HS ve nha lam cae bai,tap 1, 2, 3, 4, 5 SGK

- On lai cac kien thflc da hpe bai 43 SGK va cac khai niam hat, sdng

BAI44

THUYDT LUONG TtT A N H SANG

L U Q N G T I N H SONG - HAT CUA A N H S A N G

I-MUCTlfiU

1 ve' kigh thflc

- Neu dupe npi dung co ban cua gia thuyet lupng tfl cua Piang va thuydt lupng tfl anh sang eua Anh-xtanh

- Vidt dupe cdng thflc Anh-xtanh vd hian tupng quang dien ngoM

- Nau dupe anh sang cd ludng tinh sdng-hat

- van dung dupe thuydt lupng tfl anh sang dd giai thich ba dinh luat quang dian

2 Ve ki nSng

- Ren luyen ki nang giai thich cac hian tupng vat li

- Ren luyen ki nang van dung cdng thiic Anh-xtanh vd hian tupng quang dian de giai thieh eac dinh luat quang dien va lam mdt sd bai tap

~ Ren luyen ki nang suy luan Idgic trong viec dp dung thuydt lupng tfl anh sang dd giai thieh eac djnh luat quang dien

- Ren luyan ki nang lam bai tap trdc nghiem khach quan nhidu lua chpn vd phdn thuyet lupng tfl anh sang

m - THifiT K £ ' HOAT D 6 N G DAY HOC

Hoat ddng cua hoc sinh Trp giup cua giao vi^n

Hoat ddng 1

Kidm tra, chuan bi dieu kien

xuat phat Dat van dd

HS suy nghl ca nhan tim eau tra ldi

- Theo thuyet dipn tfl vd anh sang,

cudng dp chum sang kich thich

cang ldn, thi dian trudng bidn thian

trong anh sang cang manh, lam

cho aiectron trorlg kim loai dao

dpng cang manh, tde dp va dpng

nang cua aiectron cang ldn Hian

tupng quang dipn se xay ra khi

dpng nang cua aiectron dat dupe

gia trj du ldn de aiectron bflt ra

khdi bd mat kim loai Vay theo

thuydt lupng tfl anh sang, mudn

hian tupng quang dian xay ra thi

cudng dp 6hum sdng kich thich

phai ldn hon mpt gidi ban nao dd;

draig nang cua aiectron quang dien

phu thupc vao cudng dp chum

sang kich thich Ket luan nay mau

thudn vdi cac dinh luat quang dien

GV nau cau hdi kidm tra kien thflc cu

- Sfl dung thuydt dian tfl dd giai thi'eh cac dinh ludt quang dian

Ddt vdn de : Ta da biet, dung thuyet

dian tfl vd anh sang khong giai thich dupe cae dinh luat quang dipn Mudn giai thieh dupe cae dinh ludt quang dian

ta edn phai sfl dung mpt tinh chdt khdc eua anh sang ma khdng phai la tinh chdt sdng vay tinh chat dd la gi? Bai hpe ngay hdm nay giup ehung ta tra ldi eau hdi dd

Hoat ddng 2

Tim hieu thuyet lupng tfl anh sang

HS chu y ldng nghe

HS tiep thu, ghi nhd

GV gidi thiau vd gia thuydt lupng tfl nang lupng cua Plang

- Nam 1900, nha vat li ngudi Dfle Plang

da dd xudng gia thuydt ve lupng tfl nang lupng nham giai thich sy phat va ha'p thu bfle xa cua cae vat, dac biat la cae vat ndng sang

- Theo Plang thi lupng nang lupng ma mdi lan mpt nguyen tfl hay phan tfl hdp thu hay phat xa cd gia tri hoan toan xac dinh, gpi la lupng tfl nang lupng Lupng tfl nang lupng, ki hieu la e, cd gia tri bang: 8 = hf

Trong dd f la tdn sd eua anh sang bi hdp thu hay dupe phat ra ; h la mpt hang sd, gpi la bang sd Plang, h = 6,625 lO-^'^J.s

GV gidi thieu npi dung thuyet lupng tfl anh sang

- Nam 1905, dd giai thieh dinh luat quang dian, nha bac hpc Anh - xtanh,

da phat tridn gia thuyet cua Plang lan mpt budc va dd xudt thuyet lupng tfl anh sang (cdn gpi la thuyet phdtdn) Ndi dung cua thuyet lupng tfl anh sang:

1 Chum anh sang la mdt chum eac phdtdn (cae lupng tfl anh sang) Mdi phdtdn ed nang lupng xa djnh e = hf (f

la tdn sd cua sdng anh sang don sac tuong flng) Cudng dp cua chum sang ti

la vdi sd phdtdn phat ra trong 1 gidy

2 Phan tfl, nguyan tfl, aiectron phat

xa hay hdp thu anh sang, cung cd nghia la ehung phat xa hay hdp thu phdtdn

HS lam viec ea nhan tim cau tra ldi

- Na'u chum sang la don sdc dd thi

cd mpt loai phdtdn flng vdi anh sang

GV yau cdu HS tra ldi cac cau hdi sau

de hidu vd thuydt lupng tfl anh sang

- Hay tinh nang lupng cua phcton flng vdi anh sang dd cd bude sdng

X = 0,15\im

- Trong chum sang mau dd cd may loai

phdtdn ?

Hoat ddng 3

Ap dung thuyet lupng tiir anh

sang de giai thich cac dinh luat

quang dien

HS thao luan ehung toan ldp

- Nang lupng 8 cung cdp cho

aiectron dupe sfl dung dd : eung

cdp cho aiectron mpt cdng de nd

thoat ra khdi bd mat kim loai,

truyen cho nd mpt dpng nang ban

ddu va truyen mpt phdn nang

lupng cho mang tinh the

- Khi aiectron ndm ngay tran be

mat tinh the

Ap dung djnh luat bao toan nang

lupng, ta cd :

GV nau eau hdi de HS tim hidu cdng thflc Anh - xtanh vd hien tupng quang dian

- Trong hien tupng quang dien, gia sfl electron trong kim loai hdp thu hoan toan photon cua anh sang kich thich Nang lupng nay dupe dung de lam gi ?

- Khi nao thi aiectron thoat ra khdi bd mat kim loai va ed dpng nang cue dai?

- Gpi A la cong cdn cung cap cho aiectron d bd mat kim loai, ap dung djnh luat bao toan nang lupng ta ed bidu thflc nhu the nao ?

hf = A + mv Omax

HS thao luan ehung toan ldp

- Theo cdng thflc

2

hf = A + ^^^Q"'^ mudn eho hian

2

tupng quang dian xay ra, nghia la

mudn eho aiectron bat ra khdi bd

mat kim loai dung lam catdt, thi

phdtdn cua anh sang chieu vao catdt

phai cd nang lupng :

X A ^

he

vay XQ= — chinh la gidi ban

quang dien cua kim loai lam catdt

- Cudng dp eua ddng quang dian

bao hoa ti le thuan vdi sd quang

aiectron bdt ra khdi catdt trong mot

don vi thdi gian Vdi cac chum

sang cd kha nang gay ra hipn

tupng quang dien, thi sd quang

aiectron bi bat ra khdi mat catdt

trong mpt don vj thdi gian lai ti la

thuan vdi sd photon den dap

vao mat catdt trong thdi gian dd

GV thong bao

- Cdng thflc bf = A + ^ ^ ^ ^ ^ la edng thflc Anh-xtanh vd hien tupng quang dian

GV nau eau hdi dd HS giai thieh cdc dinh luat quang dien

- Sfl dung thuydt lupng tfl anh sang va edng thflc Anh-xtanh vd hipn tupng quang dien de giai thich ba djnh luat quang dian ?

GV nau cau hdi gpi y

- Mudn eho aiectron bat ra khdi bd mat tdm kim loai dung lam eatot thi nang lupng cua phdtdn dnh sang chidu vao cd gia tri nhd nhdt bang bao nhiau ?

- Cudng dp ddng quang dipn bao hod phu thupc nhu thd nao vao sd aiectron quang dian trong mpt don vi thdi gian ?

- Sd aiectron bi bat ra khdi bd mat catdt phu thupc nhu the nao vao cudng dp chum sang kich thich ?

Sd phdtdn nay ti la vdi cudng dp

eua chum sang tdi Tfl dd suy ra,

cudng dp eua ddng quang dipn bao

hod ti le thuan vdi cudng dp eua

chum sang chia'u vao catat

Suy ra dpng nang eye dai ban

ddu phu thupc vao budc sdng ciaa

anh sang kieh thich vd ban chdt

kim loai dung lam catdt

Hoat ddng 4

Tim hieu luong tinh sdng hat cua

dnh sang

HS thao luan ehung toan ldp

- Ngudi ta sfl dung tinh ehdt sdng

ciia dnh sang de giai thich hian

tupng giao thoa

- Ngudi ta sfl dung tinh chdt hat

cua dnh sang dd giai thich hian

tupng quang dian

- Anh sang ed budc sdng cang ldn,

phdtdn flng vdi nd cd nang lupng

cang ldn Anh sang thd hipn rd tinh

chdt hat nhu d hian tupng quang

dian kha nang ddm xuyan ldn, lam

phat quang NgUpe lai anh sang

cd budc sdng cang dai thi tinh chdt

sdng thd hien cang rd

- Dya vao cdng thflc Anh-xtanh vd hian tupng quang dien, hay eho biet dpng nang eye dai ban ddu phu thupc vao nhflng yeu td nao ?

GV nau cau hdi dd HS hieu ro ludng tinh sdng hat eua anh sang

- Chung ta da hpc nhflng tinh chat nao cua anh sang ?

- Ngudi ta sfl dung tinh chdt sdng cua anh sang de giai thieh hidn tupng gi da hpc?

- Ngudi ta sfl dung tinh chdt hat cua anh sang dd giai thieh hian tupng gi da hpe ?

- Tinh chat sdng cua dnh sang thd hian rd khi anh sang cd budc sdng nhu thd nao ?

- Tinh chdt hat eua anh sang the hian ro khi anh sang cd budc sdng nhu the* nao ?

Hoat ddng 5

Cung cd bai hpc va dinh hudng

nhiem vu hpc tap tie'p theo

GV the che hoa kidn thflc

- Nhu vay, anh sang vfla cd tinh chat sdng, vfla ed tinh ehdt hat Ngudi ta ndi rang, anh sang ed ludng tinh sdng-hat

- Trong mdi hien tupng quang hpc, anh sang thudng thd hien ro mpt trong hai tinh cha't tran Khi tinh eha't sdng thd hien ro, thi tuih ehdt hat lai md nhat, va ngupe lai

GV yau cdu HS lam bai tap trong phia'u 'hpe tap dd eung cd bai hpc

- HS vd nha lam cae bai tap 4, 5 SGK

PHI^U HOC TAP

Cau 1 Chpn cum tfl thich hpp didn vao d trdng

Theo gia thuyet lupng tfl cua Plang thi nang lupng eua

ludn bang mpt sd nguyan lan lupng tfl nang lupng

A mpi aiectron B mpi nguyan tfl

C phan tfl eua mpi ehdt D mpt chum sang don sdc

Can 2 Theo thuyet phdtdn eua Anh-xtanh, thi nang lupng

A ciaa mpi phdtdn ddu bang nhau

B eua mpt photon bang mpt lupng tfl nang lupng

C giam ddn, khi phdtdn cang rdi xa ngudn

D cua photon khdng phu thupc budc sdng

Cau 3 Cong thflc Anh-xtanh vd hian tupng quang dian la

BAI45 BAI TAP Wt mfiN TUONG QUANG DifiN

l - M U C T l £ u /'-:'•'

1 Vi kie'n thflc

- Ndm ehdc va bidt van dung edng thflc Anh-xtanh va eac cong thflc khae ed lian quan den hian tupng quang dian dd giai thich cac bai tap vd hian tUpng quang dien

- 6n tap lai kia'n thflc bai 43 va 44

Ill - THifiT K£' H O A T D 6 N G DAY HOC

Hoat ddng cua hpc sinh

Hoat ddng 1

Kiem tra, chu^n bj dieu kien

xua't phat

HS suy nghi ea nhan tim cau tra ldi

Trp giup cua giao vi^n

GV nau cau hdi kidm tra kien thflc cu

- Via't cdng thflc Anh-xtanh vd hian tupng quang dian?

- Phat bieu ba djnh luat quang dien

- Phat bidu thuyet lupng tfl anh sang ciaa Anh-xtanh

Hoat ddng 2

Lam bai tap 1 de biet each van

dung cong thflc Anh-xtanh va

cac cong thflc cd lien quan vd

hien tupng quang dien

HS lam bai tap theo nhdm, sau dd

dai dien nhdm lan bao cao kdt qua

GV ndu cac cau hdi gpi y

- Gidi han quang dian cua kim loai dung lam catdt dupe tinh theo edng thflc nao?

- Sfl dung bidu thflc nao dd ed thd xac djnh dupe van tde ban ddu eye dai ciia aiectron quang dien ?

Ne'u y nghia cua hiau dipn thd ham

- Mudn tinh dupe hiau sudt lupng tfl ta cdn phai xac dinh dupe nhiing dai lupng nao?

Sd hat phdtdn tdi catdt mdi giay:

N = — « 3 , 0 8 1 0 ' ^ h a t

e

Guong dp ddng quang dian bao

hoa l^h = ne, vdi n la sd aiectron

bflt ra khdi mat kim loai va

chuydn vd andt trong mpt don vj

Van dung dieu kien xay ra hien

tupng quang dian de lam bai tap 2

HS lam bai tap theo nhdm, sau dd

dai dien nhdm lan bao cao ket qua

Ap dung cdng thflc Anh-xtanh ta

ed :

he 1 2

A=Y mvo^^

Thay sdtadupe: A=1,94.10"'^L

Gidi han quang dian cfla tam kim

loai :

A,Q = i ^ = 1,02.10"^ m = 1,02Hm

A

Mudn ed hidn tupng quang dien

xay ra, budc sdng X eua anh

sang kich thich phai thoa man

didu kian X < XQ DO do :

•

- Na'u tinh dupe sd quang aiectron bflt

ra trong mdt giay va sd phdtdn tdi be mat kim loai trong mpt giay thi cd thd xac djnh dupe hiau sudt lupng tfl khdng ?

- Cdng sudt eua chum sang cd lian he nhu the nao ddi vdi sd phdtdn N eua chum sang chieu tdi be mat kim loai trong I gidy?

- Cucmg dp ddng quang didn bao boa lian ha nhu the nao dd'i vdi sd quang aiectron trong 1 giay ?

GV yau cdu HS lam bai tap 2 trong phia'u hpc tap theo nhdm, sau dd dai dien nhdm lan bao cao ket qua

GV nau eac eau hdi gpi y

- Didu kien de xay ra hien tupng quang dian la gi ?

- Mudn biet hai chum sang chidu tdi i ta'm kim loai cd gay ra hien tupng quang dian hay khong ta cdn phai xae dinh dupe dai lupng nao ?

- Mudn xae djnh dupe gidi ban quang i

dien XQ ta phai xae djnh dupe dai lucmg i

nao ? Sfl dung cdng thflc nao de xac djnh dupe dai lupng dd ?

- Vdi X] thi A.] > XQ ndn hien

tupng quang dian khdng xay ra;

- Vdi X2 thi X2<A,Q nan hien

tupng quang dien xay ra khi dd,

dpng nang ban ddu eye dai eua

Tim hieu khai niem he quy chidu

va chuyen dpng tinh tien

HS lam bai tap theo nhdm, sau dd

dai dien nhdm lan bao cao kdt qua

a) Gidi ban quang dien eua ddng :

GV nau cac cau hdi gpi f

- Tai sao qua cdu tich dien ?

- Dien the cua qua cdu phu thupc nhu the nao vao sd electron bj bat ra khdi b^ mat qua cdu ?

- Theo thdi gian, didn tich eua qua cdu tang thi dian thd eua qua cdu bien ddi the nao ? Lieu cd thd tang mai khdng ?

- Khi nao dien the cua qua cdu khdng tang nfla ?

- Gia trj dien the eye dai cua qua cdu chinh la dai lupng nao trong te bao quang dian ?

Ban ddu, qua cdu chua tich dian

Khi chia'u bfle xa cd budc sdng

X vao qua cdu thi aiectron bj bflt

ra khdi mat qua cau va qua cdu

tich dien duong, qua cdu cd mdt

dian the Sd aiectron bj bflt ra

khdi mat qua cdu ngay cang

nhidu, dien thd cua qua eau tang

ddn va khi dien thd cua qua cdu

dat tdi gia trj V^^ thi cac

aiectron vfla mdi blot ra tham lai,

lai bj hut trd lai qua cdu, va dian

the cua qua cdu khdng tang nfla

vay gia trj eye dai V^ cua dipn

the qua cdu chinh la hieu dien

the ham trong td bao quang dien

- Dya vao cau b ta ed the tinh van tde

eye dai ban ddu cua quang aiectron nhu thd nao ?

- Mudn xac dinh budc sdng cua anh sang kich thieh ta phai ap dung cdng thflc nao ?

cau 1 Chia'u mpt chum anh sang ed budc sdng X = 0,489ta,m lan mpt tdm

kim loai kali dung lam catdt cfla mpt te bao quang dien Bidt cong thoat aiectron cua kali la 2,l5eV

a) Tinh gidi ban cua kali

b) Tinh van tde ban ddu eye dai cua aiectron bdn ra tfl catdt

c) Tinh hieu dien the ham

d) Bia't cudng dp ddng quang dien bao hda I^h =5mA va cdng sudt cua chum anh sang chidu vao catdt la S!^=1,25W, hay tinh hiau sudt lupng tfl (ti sd gifla sd aiectron bflt ra khdi mat kim loai va sd phdtdn tdi mat kim loai)

cau 2 Khi chia'u vao mpt tdm kim loai mdt chum sang don sdc cd budc song

0,2}am,dpng nang ban ddu eye dai cua aiectron quang dien la S.IQ-'^J Hdi khi chia'u vao tdm tim loai dd ldn lupt hai chum sdng

don sac cd budc sdng Xi=l,40|am va X2 =0,10|am, thi cd xay ra hien

tupng quang dien khong ? Ndu cd, hay xac djnh van tde ban ddu cue dai cua cac aiectron quang dien

cau 3 Cdng thoat cua aiectron khdi ddng la 4,47eV

a) Tinh gidi han quang dien eua ddng

b) Khi chia'u bfle xa cd budc sdng ^=^ 0,14pm vao mot qua cdu bdng ddng dat xa cac vdt khae thi qua cdu dupe tich dian den dien thd eye dai la bao nhieu ? Van tde ban ddu eye dai cua aiectron quang didn la bao nhiau ?

c) Chia'u mpt bfle xa didn tfl vao mdt qua cdu bang ddng dat xa cac vat khae thi qua cdu dat dupe dipn the eye dai 3V Hay tinh budc sdng cua bfle xa va van tde ban ddu eye dai cua aiectron quang dipn

- Dinh nghia dupe hipn tupng quang dian trong

- van dung de giai thich dupe hien tupng quang ddn

- Trinh bay dupe djnh nghia, cdu tao cua quang trd va pin quang dipn va hoat ddng cua pin quang dien

- Dy doan dupe vdi cac cudng dp chum sang khae nhau se cho gia tri cudng

dp ddng dian khae nhau

- Dd xudt phucmg an thi nghiam dd kidm tra dupe dy doan : Thay doi cudng

dp chum sang dpc gia trj cua cudng-dp ddng dian tuong ihig

2 va' ki n5ng

- Ren luyan ki nang dua ra dy doan ddi vdi mpt hian tupng vat li

- Ren kl nang lap mach dian

- Ren luyen ki nang quan sat, xfl ly thdng tin thu thap dupe:

- Ren luyen kT nang tim hieu cae ung dung ki thuat vat li

n - C H u X N B I

Gido vien

- Bp thi nghiem bidu didn vd hian tupng quang dian trong va cac flng dung

- Bp thi nghiem flng dung sfl dung quang trd trong he thdng ddng ngdt den dudng

- 4 bp thi nghiam khao sat hien tupng quang dipn trong va cac flng dung

Hpc sinh

- 6n lai cac kia'n thflc vd ddng dien trong chdt ban ddn trong chuong trinh vat li 11

nang cao va eac bai 43 va 44 SGK vat U 12 nang cao

Ill - THlfiT Kfi HOAT © O N G DAY HOC

Hoat ddng cua hoc sinh

Hoat ddng 1

Kiem tra, chuan hi dieu kien

xuat phat Dat van de

HS suy nghl ca nhan tim cau tra ldi

Trp giup cua giao vi§n

GV nau eau hdi kidm tra kia'n thflc cu

- Trinh bay hian tupng quang dian ngoai va giai thieh hipn tupng?

- Phat bidu ba djnh luat quang dian va sfl dung thuydt lupng tfl anh sang ciia Anh-xtanh dd giai thich ba djnh ludt quang dipn

Dat vdn de : Pin Mat Trdi cung cdp dian

nang cho Tram Nghian cihi vu tru qudc

td ISS boat dpng dya tren hian tupng nao ? Bai hpc nay giup chflng ta tra ldi cdu hdi dd

GV tien hanh thi nghiam lam nay sinh vdn dd cdn nghian cihi

- Lam thi nghiam thdy hipn tupng la khi chidu anh sang vao linh kipn ban dan thi thdy ed ddng trong mach, khi khdng chia'u anh sang vao thi khdng cd ddng trong mach

- Dung cu dd cd dac tinh la khi chidu sang thi cd ddng chay qua, khi khdng chia'u sang thi khdng cd ddng chay qua Ngudi ta gpi dung cu nay la quang trd

~ Trong thyc ta' ed mpt sd chdt ban din nhu: Ge, Si, PbS, PbSe, PbTe, CdS, CdSe, CdTe cd tinh chat dac bipt nhu vay gpi la tinh quang ddn

HS thao luan ehung toan ldp

- Dieu kian dd cd ddng dien la

trong mach phai cd:

+ Dien trudng (Hieu dien tha")

+ Hat tai (Hat mang dien)

- Trong hai trudng hpp da cd dian

trudng, trudng hpp chidu sang da

cd hat tai dien thi trong mach mdi

cd ddng dien

- Khi chia'u anh sang vao quang trd,

mdi phdtdn anh sang kich thieh se

truydn toan bp nang lupng eua nd

eho mpt electron lian kdt, lam giai

phdng khdi mdi Uan kdt dd trd thanh

electron din va 16 trdng tham gia

vao qua trinh ddn dipn

HS thao luan ehung toan ldp dua ra

dydoan

- Na'u tang cudng dp chum sang

till cudng dp ddng dian chay trong

mach se tang

- Tang cudng dp chum sang bang

each giam khoang each tfl ngudn

sang tdi quang trd, do cudng dp

ddng dien tuong flng

Vdn dd cdn nghian cflu : Tai sao khi chia'u anh sang vao quang trd thi quang trd ddn dipn, khi khdng chidu anh sang vao thi quang trd khdng dan dien

GV nau eac cau hdi gpi y

- Didu kian de cd ddng dien la gi ?

- Cac em quan sat trong ca hai trudng hpp cd anh sang va khOng cd anh sang chieu vao da cd didu kian nao rdi ?

- Sy khae nhau d chieu sang va khdng chia'u sang la gi ?

- Liau cd phai anh sang cung cd vai trd gidng nhu hian tupng quang dien ngoai ma ta da biet khdng

GV nau cau hdi vd vdn dd cdn nghidn cflu tia'p

- Ndu gia thuydt tran ma dung thi cudng dp chum sang ed anh hudng dah cudng dp ddng dien trong mach khdng ?

GV nau cdu hdi thidt kd phuong an thi nghiam kiem tra du doan

- Vdi bp thi nghiam vfla tidn hanh lam the nao dd kiem tra didu nay?

GV nau cau hdi gpi y

- Cdn phai tien hanh thi nghiem nhu the nao?

- Thay ddi cudng dp chum sang bdng each nao ?

HS lam thi nghiem theo nhdm, sau

dd dai dien nhdm lan bao cao ket

qua

Ket qua thi nghiem : Vdi cae

cudng dp chum sang khae nhau se

eho mpt gia trj cua cudng dp ddng

dien Tang cudng d6 chum sang

chia'u tdi quang trd thi cudng dp

ddng dien tang

HS tia'p thu, ghi nhd

- Co thd thay ddi cudng dp chum sang chia'u ldi quang trd bang each thay ddi khoang each tfl ngudn saiig tdi quang trd dupe khdng ?

*^^' yau cdu HS chia ldp thanh 4 nhdm thi nghiam, mac so dd mach dien nhu hinh ve sau vd tien hanh thi nghiem kidm tra

V

GV thdng bao

- Hien tupng tao thanh cac aiectron dan

va 16 trdng trong ban dan, do tac dung eua anh sang ed budc sdng thich hpp, gpi la hien tupng quang dien trong

- Mudn gay dupe hien tupng quang dien trong thi anh sang kich thich phai

cd bude sdng nhd hon hoac bdng nipt gia trj ^Q, gpi la gidi han quang dian ciaa ban ddn

- Vl nang lupng cdn thidt dd giai phdng aiectron lian kdt trong ban ddn thudng nhd hon cdng thoat A cua electron tir mat kim loai nan gidi ban quang dien cua nhidu ban ddn nam trong vung anh sang hdng ngoai (Thang ban vdi Ge thi

- Hien tupng giam dian trd suat, tfle la tang dp ddn dien cua ban ddn, khi cd anh sang chieu vao gpi la hien tupng quang ddn

Hoat ddng 3

Tim hieu mpt sd ihig dung cua

hian tupng quang dian trong

HS chu y ldng nghe va quan sat

tran hinh ve

HS chu y quan sat va lang nghe

GV gidi thieu eau tao cua quang trd da sfl dung lam thi nghiem d tran

- Quang trd sfl dung trong thi nghiem tran dupe che tao dua tren hieu img quang dien trong Dd la mpt tdm ban ddn cd gia tri dien trd thay ddi khi cudng

dp chum sang chieu vao nd thay ddi

- So dd mach dien dung quang trd nhu tran Ldp ban ddn mdng (2) dupe phu lan dd each dien (1) cd be day chiing 20-^30|am Tfl hai ddu cua ldp ban ddn, ngudi ta lam eac dien eye (3) bang kim loai va ddn ra ngoai bang cac day ddn (4) Mach ngoai ndi vdi dien ke (5), mpt dien trd tai va ngudn dien (6)

- Quang trd thudng dupe lap vdi mach khuech dai trong eac thiet bj dieu khidn bang anh sang VD : mach dieu khidn den chidu sang tran dudng, trong cac may do anh sang

GV tidn hanh thi nghiem ve irng dung quang trd trong he thdng den dudng va giai thich flng dung

r /

lOBOliNCOUflG sit DUNG DUAHnTBCflROHCHEIHfiNtflEHftinlNS ,^

- Ban ngay, khi anh sang chidu vao

quang trd du manh thi dien trd cua nd r^t nhd so vdiRi- Hiau dipn thd UBE cung se rdt nhd Ddng eye bazo Ig khdng cd va, do dd, ddng cdlecto I^- se bang khdng Role khdng boat dpng

- Ban tdi, khi anh sang chieu vao quang trd yeu ddn mflc nao dd thi dipn trd ciia

nd se du ldn Hipu dipn thd Ugg tang Khi Ug£ dat ddn mpt gia tri nao dd thi xudt hian ddng cue bazo va do dd, xudt hipn ddng cdlecto I^ Ddng I^ chay qua role lam cho nd boat dpng va ddng mach thdp sang cac den dudng

GV gidi diipu ca'u tao va nguyan tde boat dpng eua pin quang dipn, yau cdu

HS quan sat so dd ca'u tao

^ ^y \|/ \^ >y

+

Dien circ trong sudt -f- Ban din loai p Ban dia loai n Dien circ

HS thao luan ehung toan ldp

- Khi anh sang ed budc sdng thich

hpp {X<XQ) chieu vao ldp kim

loai mdng d tran ciang thi anh

sang se di xuyan qua ldp nay vao

ldp ban ddn loai p, gay ra hien

tupng quang dien trong va giai

phdng ra eae cap aiectron va 16

trdng Dien trudng d ldp chuydn

tidp p-n ddy Id trdng vd phia ban

ddn loai p va ddy aiectron vd

phia ban ddn loai n Do dd, ldp

kim loai tran ldp ban ddn loai p

se nhidm dian duong va trd thanh

dien eye duong cua pin, cdn ldp

kim loai dudi ban ddn loai n se

nhidm dian am va trd thanh dian

cue am

- ca'u tao cua pin quang dien gdm mpt tdm ban ddn loai n, ban tran cd phu mpt

1 ^ mdng ban ddn loai p Mat tren cung

la mpt ldp kim loai mdng trong sudt vdi anh sang va dudi cung la mpt dd kim loai Cae ldp kim loai nay ddng vai trd

Id cae dian cue

GV nau cau hdi dd HS tim hidu boat dpng cua pin quang dian

- Hay cho biet pin quang dien boat dpng nhu thd nao ?

GV nau eac cau hdi gpi y

- Khi cd anh sang thich hpp chidu vao ldp kim loai trong sudt thi ed hian tupng

gi xay ra ?

- Cac electron va Id trdng se djch ehuydn nhu the nao ? Tai sao ?

- Dian eye nao ddng vai trd la dian eye ducfng, dm

Hoat ddng 4

Cling cd bai hpc va dinh hudng

nhiem vu hpc tap tie'p theo

HS suy nghl ca nhan tim eau tra ldi

xa d nude ta, tran cae va tinh nhan tao, eon tau vu try, trong eae may do anh sang, may tinh bd tui

GV nau eau hdi cung cd kidn thflc

- Tai sao tia hdng ngoai chi cd thd gay

ra dupe hian tupng quang dien trong, cdn tia tfl ngoai mdi gay ra dupe hian tupng quang dian ngoai ?

- HS ve nha lam cac bai tap 1,2,3 SGK

- On lai thuyat lupng tu anh sang va kia'n thflc vd cdu tao nguyan tfl trong mon hoa hpe

- Phat bidu dupe eac tian dd cua Bo

- Md ta dupe cae day quang phd vach cua nguyan tfl hidrd va nau dupe co che tao thanh cac day quang phd vach phat xa va hap thu cua nguyan tfl nay

- Giai dupe eae bai tap vd tinh bude sdng cac vach quang phd eua nguyan tfl hidrd

2 Va' ki n i n g

- Ren luyan ki nang giai thich sy tao thanh quang phd vach cua nguyan tfl hidrd

- Ren luyen kT nang thu thap thdng tin khi dpc tai lieu

- Ren luyen ki nang lam eac bai tap trdc nghiam khach quan nhidu lya chpn phdn mdu nguyan tfl Bo va quang phd vach cua nguyan tfl hidrd

II-CHUXNBI

Gido vien

- Ve hinh 47.3 va 47.4 SGK tran cung mpt td gia'y khd AQ

- Chuan bi phieu hpe tap

Hpc sinh

- On lai thuyet lupng tfl anh sang va ve cdu tao nguyan tfl trong mon hoa hpc

Ill - THifiT Kfi HOAT D 6 N G DAY HOC

Hoat ddng cua hpc sinh

Hoat ddng 1

Kiem tra, chuan bi dieu kien

xuat phat Dat van de

HS suy nghl ea nhan tim cau tra ldi

Trp giup cua giao vien

GV nau cau hdi kiem tra kien thflc cu

- Phat bieu thuyet lupng tfl cua xtanh

Anh-HS nhan thflc dupe van de eua bai

hoc

Ddt vdn de : Bai 39 chflng ta da bidt

quang phd vach phat xa cua nguyan tu hidrO Giai thich sy tao thanh quang phd nay nhu thd nao Bai hoc ngay horn nay giup chflng ta tra ldi cau hdi dd

Hoat ddng 2

Tim hieu cac tien de cua Bo

HS lam viec ca nhan

- Nguydn tfl chi tdn tai trong

mpt sd trang thai cd nang lupng

xac dinh E^, gpi la cac trang

thai dflng Khi d trang thai dflng,

nguyan tfl khdng bfle xa

- Trang thai dflng la trang thai cd

nang lupng xac djnh

- Trang thai dflng cd nang lupng

thap nha't gpi la trang thai co ban

Cac trang thai dimg cd nang lupng

cao hon gpi la trang thai kich thieh ,

- Thdi gian sdng tmng binh eua eac

nguyan tfl trong cae trang thai kich

thich rdt ngdn (chi cd 10"^s) Sau

dd nguyan tfl chuydn ve cae trang

thai dflng cd nang lupng thdp hon,

va cudi ciing vd trang thai co ban

- O trang thai dflng, ban kinh quy

dao chuyen dpng cua aiectron

hoan toan xae djnh Cac quy dao

chuyen dpng cua aiectron khi

nguyan tfl d trang thai dflng gpi la

quy dao dimg

GV yau cdu HS dpc mue 1 SGK dd tim

hidu eae tian dd cua Bo, sau do tra ldi

cae eau hdi sau day kidm tra sy thu thap thdng tin khi dpc SGK

- Npi dung tian de vd trang thai dflng

- Trang thai dflng la trang thai nhu thd nao?

- Trang thai dflng cd nang lupng thdp nhat gpi la gi ? Cac trang thai edn lai gpi la gi ?

- Nhan xet gi vd thdi gian sdng trung binh cua cae nguyan tfl trong eac trang thai kieh thieh

- Xu hudng sdng eua cac nguyan tfl d trang thai nao

- Ci trang thai dimg, ban kinh quy dao chuydn dpng cua aiectron ed dac diem

- Quy dao diing cua aiectron trong

nguyan tfl hidrd : r„ = n \ trong dd

n la sd nguyan va n = 1, 2, 3,

tuong flng vdi tan eac quy dao diJmg

K , L , M r o - 5 , 3 1 0 " " m goi la

ban kinh Bo

- Khi nguyen tfl chuydn tfl trang

thai di^g cd ndng lupng E^

sang trang thai dflng cd nang

lupng E^^ nhd hon thi nguyan tfl

phat ra mpt phdtdn cd nang

lupng dung bang hiau E^, E j ^

Ngupe lai, ndu nguyan tfl dang

d trang thai dflng cd nang lupng

E^i ma ha'p thu dupe mpt photon

cd nang lupng hf dung bang hieu

En -E^^ thi nd chuyen sang

trang thai dimg cd nang lupng

Ej, ldn hon

- Theo tian de vd sy bfle xa va hdp

thu nang lupng eua nguyan tfl,

mudn nguyan tfl d trang thai co ban

chuyen sang trang thai kich thich

thi nguyen tfl phai hdp thu mpt

phdtdn cd nang lupng dung bang

hiau hai mflc nang lupng tran

- Mudn nguyan tfl dang d trang

thai kich thich mudn chuyen vd

trang thdi kich thich ed nang lupng

nhd hon thi nguyan tfl phai phat xa

- Nau cdng thflc tinh ban kinh quy dao dflng ciaa aiectron trong nguyan tfl hidro va giai thich y nghia cac dai lupng trong cong thflc dd ?

- N p i dung tien dd vd sy bfle xa va hdp thu nang lupng ciaa nguyan tfl

- Khi nguydn tfl dang d trang thai ca

ban mudn ehuydn sang trang thai kich thich thi nguyan tfl phai the nao ?

- Khi nguyan tfl dang d trang thai kich thich mudn chuyen vd trang thai kich thich cd nang lupng nhd hon phai the nao?

'm

Hoat ddng 3

Giai thich su tao thanh quang

phd vach ciia nguyen tfl hidrd

HS quan sat hinh ve va thao ludn

ehung toan ldp

- Khi aiectron d cdc quy dao dflng

K, L, M, N thi nguyan tfl hidrd d

cae trang thai dimg cd mflc nang

lupng tuong flng la E|, E2, E3,

E4

- Mflc nang lupng th^p nhdt la E,,

khi nguyan tfl hidrd d trang thai cd

mflc nang lupng nay thi aiectron

chuyen dpng tran quy dao dflng K

- Khi chup anh quang phd cua

nguyan tu hidrd ngudi ta thu dupe

ba day quang phd: Lai-man,

Ban-me Pa-sen

GV yeu cdu HS quan sat hai hinh 47.3

va 47.4 dupe ve tran cung mpt khd gidy

AQ, sau dd tra ldi cac cdu hdi sau dd giai thich sy tao thanh quang phd vach ciia nguyan tfl hidrd

- Quan sat tran hinh ve hay cho bidt: khi aiectron d cdc quy dao dflng K, L,

M, N thi nguyan tit hidrd d cae trang

thdi dflng ed mflc nang lupng tucmg flng nao '

- Mflc nang lupng ndo Id thafp nhdt, khi nguyan tfl hidrd d trang thai diJmg c6 mflc nang luong thdp nhdt thi aiectron chuydn dpng d quy dao nao ?

- Nhin vao hinh ve, hay cho bidt khi chup anh quang phd cua nguyan tfl hidrd ngudi ta thu dupe may day quang phd ? Kd tan eae day quang phd ?

- Day Lai-man dupe tao thanh khi

aiectron chuydn tfl eac quy dao

dimg ban ngoai ve quy dao K:

L ^ K; M ^ K ; N ^ K Day

Ban - me dupe tao thanh khi

aiectron tfl eac quy dao ngoai vd

quy dao L : M -> L ; N ^ L ;

0 -> L ; P -> L Day Pa-sen

dupe tao thanh khi aiectron chuyen

tfl cdc quy dao ben ngoai ve quy

daoM

- Bdn vach quang phd dd H^^,

lam Hp, cham H.^, tim Hg thupc

day quang phd Ban-me Cac vach

dd dupe tao thanh khi aiectron

chuydn tfl quy dao M, N, 0 , P vd

quy dao L

Hoat ddng 4

Cung cd bai hpc va dinh hudng

nhiem vu hpc tap tie'p theo

HS suy nghl ca nhan tim cau tra ldi

- Hay ndi ro sU ehuydn cac mflc nang lupng cua nguyan tfl hidrd va sy chuyen quy dao dflng tuong flng vdi cac mflc nang lupng cua aiectron trong cac day quang phd dd ?

- Bdn vach quang phd dd H^^, lam Hp, cham H^, tim Hg thupc day quang phd nao ? Tuong flng vdi cae vach dd thi aiectron chuydn tfl quy dao ban ngoai nao vd quy dao nao ?

GV yau cdu HS lam cae bai tap trac nghiam trong phieu hpc tdp de cung ed bai hpc

- HS vd nha lam bai tap 4 SGK

- On lai cac kidn thflc ve quang phd hdp thu

PHlfiu HOC T^P

cau 1 Trang thai dflng cua mpt nguyan tu la

A trang thai dung yan cua nguyan tfl

B trang thai chuyen dpng ddu cua nguyan tfl

C trang thai trong dd mpi aiectron ciaa nguyan tfl deu khong chuyen dpng ddi vdi hat nhan

D mpt trong sd eac trang thai cd nang lupng xac djnh, ma nguyan tfl dd

cd thd tdn tai

cau 2 d trang thai diing, nguyan tfl

A khdng bfle xa va khong hdp thu nang lupng

B khdng bfle xa, nhung ed the hap thu nang lupng

C khdng ha'p thu, nhung cd thd bfle xa nang lupng

D vdn ed the hap thu va bfle xa nang lucmg

cau 3, Day Ban-me ihig vdi sy chuyen aiectron tfl quy dao d xa hat nhan vd quy

dao nao trong cac quy dao sau day ?

A Quy dao K

B Quy dao L

C Quy dao M

D Quy dao N

- Hieu dupe sy phan xa loc lya la gi ?

- Giai thich dupe tai sao cac vat cd mau sdc khae nhau

2 va" ki nang

- Ren luyen kl nang giai thich cac hian tupng vat li

- Ren luyen kl nang lam cac bai tap trdc nghiem khach quan nhidu lya chpn phdn hdp thu va phan xa Ipc lya anh sang

II-CHUXNBI

Gido vien

- Mpt sd ta'm kinh mau

- Chudn bj phieu hpc tap cho HS

Hpc sinh

- On lai cac kien thflc vd quang phd hap thu

Ill - THifiT Kfi HOAT D 6 N G DAY HOC

Hoat ddng cua hpc sinh

Hoat ddng 1

Kiem tra, chuan bi dieu kien

xuat phat Dat van de

HS suy nghl ca nhan tim cau tra ldi

Trp giup cua giao vien

GV nau cau hoi kidm tra kien thflc cu

- Quang phd vach hdt thu cd the thu dupe trong didu kien nao ? Nau dac didm cua quang phd vach ha'p thu

HS nhan thflc dupe vdn dd eua bai

hoe

Ddt vdn de : Dudi anh sang trdng cua

bdng den day tde ta quan sat thdy eae vat CO cac mau sac khdc nhau Tai sao lai nhu vay ? Bai hpc ngay hdm nay giup ta tra ldi eau hdi dd

Hoat ddng 2

Tim hidu su h^p thu anh sang

HS tia'p thu, ghi nhd

HS thao luan ehung toan ldp

- Tdm thuy tinh se ndng lan do

ha'p thu quang nang cua chum sang

- Don vj cua cudng dp sang la oat tran met vudng (W/m )

GV nau cau hdi dd HS tim hieu sy hdp thu anh sang

- Chia'u chum sang qua mpt tdm thuy tinh mau dd (vi du nhu den pin) khoang

10 phut, sd tay vao ta'm thuy tinh thi thdy hian tupng gi ? Giai thich tai sao ? Nhan xet gi vd cudng dp chum sang I thu dupe sau khi qua tdm thuy tinh va cudng dp chum sang IQ trudc khi chieu qua ta'm thuy tinh?

GV thdng bao

- Ha'p thu anh sang la hien tupng mdi trudng vat chdt lam giam cudng d6 eua chum sang truyen qua nd

- Viec khao sat djnh lupng sy hdp thu

anh sang cho thdy: Cudng d6 I ciia

chum sang don sdc khi truyen qua mdi trudng hdp thu, giam theo dinh luat ham mu cua dp dai d cua dudng

di tia sang : I=Ioe""''

HS thao luan ehung toan ldp

- Ta quan sat dupe bd'n vach quang

phd ha'p thu Id nhflng vach tdi tai

dflng cac vi tri vach dd H^, lam

Hp, chdm Uy, tim Hg tran ndn

quang phd lien tuc

HS tidp thu, ghi nhd

•;vv/-^ •;

•'•••'• " ^ '

vdi IQ Id cudng dp cua chum sang tdi mdi trudng, a dupe gpi la ha sd hdp thu ciaa mdi trudng

Dd chinh la npi dung djnh luat vd sy ha'p thu anh sang

GV nau eau hdi dd HS tim hidu sy ha'p thu loc lya

- Khi cho chflm sdng trang qua dng thuy tinh cd khi hidrd nung ndng vao may quang phd thi ta thu dupe quang phd nhu thd nao ?

- Mpi chdt ddu hdp thu ed chpn Ipc anh sang Nhung ehdt hdu nhu khdng hdp thu anh sang trong midn nao cua quang phd dupe gpi la gdn trong sudt vdi midn quang phd dd

- Nhflng vai khdng hdp thu anh sang trong mien nhin tha'y cua quang phd dupe gpi la vat trong sudt khdng mau (chang han nhu nude nguyan ehdt, khdng khi, thuy tinh khdng mau ) Nhflng vat ha'p thu hoan toan vdi anh sang nhin tha'y thi cd mau den

Hoat ddng 3

Tim hieu sy phan xa hoac tan xa

loc lua va mau sac cac vat

HS thao luan ehung toan ldp

- Mudn nhin thdy cac vat thi anh

truyen tdi vat phai phan xa hoac

tan xa tdi mdt ngudi quan sat

- Khi nhin thdy vat mau dd chflng

td vat phan xa hoac tan xa anh

sang dd tdi mat va hap thu hdu bet

cac anh sang cdn lai

- Khi khdng cd anh sang mau nao

truydn tdi mdt thi quan sat tha'y vat

cd mau den

HS tia'p thu, ghi nhd

- Nhung vat hdp thu loc lya anh sang trong midn nhin thay thi dupe gpi la vat trong sudt cd mau

GV nau cau hdi de HS tim hidu sy phan

xa hoac tan xa va mau sdc cac vat

- Tai sao ehung ta lai nhin thdy cac vat cd mau sdc khae nhau khi chflng dupe chidu sang bdi cung mpt ngudn sang trdng ?

GV nau eau hdi gpi y

- Mudn nhin tha'y cac vat thi anh sang

phai dupe truyen nhu tha' nao?

- Nhin tha'y vat mau dd chflng td anh sang mau nao dupe truyen tdi mat?

- Khi khdng ed anh sang mau nao truydn tdi mdt thi ta quan sat thdy vat mau gi ?

GV thong bao

- Mpt sd vat, kha nang phan xa (hoac tan xa) anh sang manh, ydu khae nhau phu thupc vao budc sdng anh sang tdi

Cd nhiing vat phan xa (hoac tan xa) manh cae anh sang cd bude sdng dai, nhung phan xa (hoac tan xa) yeu cae anh sang cd bude sdng ngan Dd la sU phan xa cd loc lya

- Khi chieu mpt chum sang trdng vao mpt vat, thi do vat ed kha nang phan xa (hoac tan xa) loc lya, nen anh sang phan

xa (hoac tan xa) la anh sang mau Didu

dd giai thich lai sao cac vat ed mau sdc khae nhau

Hoat ddng 4

Cung cd bai hpc va dinh hudng

nhiem vu hpc tap tia'p theo

- Cac vat the khae nhau cd mau sdc khae nhau la do ehung dupe eau tao tfl nhihig vat lieu khae nhau Khi ta chidu anh sang trdng vao vat, vat hdp thu mpt

sd anh sang don sdc va phan xa, tan xa, hoac cho truyen qua cac anh sang don sdc khae

GV yeu cau HS lam eac bai tap trong phia'u hpc tap dd cung cd kien thflc

- HS on tap cac kien thflc bai 45

PHlfiu HOC TAP

cau 1 Cudng dp cua chum sang don sdc truydn qua moi trudng hap thy

A giam ti le vdi dp dai dudng di cua ti^ sang

B giam ti le vdi binh phuong dp dai dudng di cua tia sang

C giam theo djnh luat ham mu cua dp dai dudng di ciaa tia sang

D giam theo ti le nghjch vdi dp dai dudng di cfla tia sang

Cau 2 Khi chieu vao tam bia dd chiim sang tim, ta thay tam bia cd mau

A tim B dd

C vang D den