Đề kiểm tra và Đáp Án môn vật lý a2 dao Động electromagnetic waves physics a2 test 2

For an electromagnetic wave the direction of the vector gives: A.. The electric field vector has a maximum value of 175 V/m and vibrates in the xy plane... Calculate the average value of

Department of Engineering Physics

PHYSICS A2

TEST 2

Student’s name:

Student ID:

MCQ ANSWER SHEET :

Choose for each question only one correct answer and darken corresponding circle

in the following answer sheet

1

Displacement current is:

A dΦE/dt

B ε0dΦE/dt

C µ0dΦE/dt

D µ0ε0dΦE/dt

2

Displacement current exists wherever there is:

A a magnetic field

B moving charge

C a changing magnetic field

D a changing electric field

3

For an electromagnetic wave the direction of the vector gives:

A the direction of the electric field

B the direction of the magnetic field

C the direction of wave propagation

D the direction of the electromagnetic force

on a proton

4

The product µ0ε0 has the same units as:

A (velocity)^2

B (velocity)^1/2

C 1/velocity

×D 1/velocity^2

* Situation for questions 5, 6

A linearly polarized microwave of wavelength 1.50 cm is directed along the

positive x axis The electric field vector has a

maximum value of 175 V/m and

vibrates in the xy plane

5

Find the wave number

A 567rad/m

B 467rad/m

C 167rad/m

D 419rad/m

6

Calculate the average value of the Poynting vector for this wave

A 56,7W/m^2

B 48,7W/m^2

C 66,6W/m^2

D 40,6W/m^2

* Situation for questions 7-10

A plane electromagnetic wave varies sinusoidally at 90.0 MHz as it travels along the

x direction The peak value of the electric field

is 2.00 mV/m, and it is directed along

the y direction

7

Find the wavelength

A 3,3m

B 4,3m

C 2,3m

D 20m

8

Find the period T

A 11ns

B 43ns

C 23ns

D 20ns

9

Find the maximum value of the magnetic field

Bmax

A 26pT

B 8pT

C 15pT

D 6,67pT

10 Find the average power per unit area that this wave carries through space?

A 5,31.10−9 W / m2

B.5,31.109 W / m 2

C.5,31.103 W / m 2

D 5,31.10−3 W / m 2

Problems:

* Situation for questions 11-15

The electric potential has the form At the point A(-4,3,6) in the

vacuum find:

11 the electric field

12 the density of electric energy

13 the volume density of charge

14 the conducting current density

15 the displacement current density

* Situation for questions 11-15

The electric field has the form Find:

16 the magnetic field

17 the vector Poynting

18 the density of magnetic energy

ĐÁP ÁN

1 Displacement current is:



A dΦE/dt





B ε0dΦE/dt





C µ0dΦE/dt





D µ0ε0dΦE/dt



2 Displacement current exists wherever there is:



A a magnetic field



B moving charge





C a changing magnetic field





D a changing electric field



3 For an electromagnetic wave the direction of the vector gives:



A the direction of the electric field





B the direction of the magnetic field





C the direction of wave propagation





D the direction of the electromagnetic force on a proton



4 The product µ0ε0 has the same units as:



A (velocity)^2





B (velocity)^1/2





C 1/velocity





D 1/velocity^2



5 Find the wave number:



A 567rad/m





B 467rad/m





C 167rad/m





D 419rad/m



6 Calculate the average value of the Poynting vector for this wave:



A 56,7W/m²





B 48,7W/m²





C 66,6W/m²





D 40,6W/m²



7 Find the wavelength:



A 3,3m





B 4,3m





C 2,3m





D 20m



8 Find the period T:



A 11ns





B 43ns





C 23ns





D 20ns



9 Find the maximum value of the magnetic field Bmax:



A 26pT



B 8pT





C 15pT





D 6,67pT



10 Find the average power per unit area that this wave carries through space:



A 5,31 × 10 W / m²⁻⁹





B 5,31 × 10 W / m² ⁹





C 5,31 × 10³ W / m²

D 5,31 × 10 ³ W / m²⁻

11 Điện trường

Điện trường được xác định bởi gradient của điện thế:

14 Mật độ dòng dẫn điện

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15 Mật độ dòng dịch chuyển

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