Đề IPHO(vật lí quốc tế) 1983-4

IPhO 1983 Theoretical Question III MARKING SCHEME FOR ANSWERS TO THE THEORETICAL QUESTION III -OPTICS Marking scheme – Prisms Page 1 of 3... IPhO 1983 Theoretical Question III Marking sc

IPhO 1983 Theoretical Question III

MARKING SCHEME FOR ANSWERS TO THE THEORETICAL QUESTION III

-OPTICS

Marking scheme – Prisms

Page 1 of 3

IPhO 1983 Theoretical Question III

Marking scheme – Prisms

Page 2 of 3

Scores III a. For:

( )0 2( )0

n = 0.50p

1 2

2 1

b b

−

−

=

λ 0.25p

final result: λ0= 500nm 0.25p

n1( ) λ0 =n2( ) λ0 =1,5 0.25p

1.25 points

III b. For the rays with different wavelength (λred , λ0 , λviolet) having the same incidence

angle on first prism, the paths are illustrated in the figure III.1

Figure III.1

2.00 points

III c. For:

( ) ( )

2

' sin 2

'

0 2 0

A n

n

+

=

=

δ λ

λ 0.25p

( )Aˆ' = 30 °

m 0.25p

2

' 2

' sin 2

3 arcsin 2 min A −A









 ⋅

=

δ 0.25p

final result: δmin ≅30,7° 0.25p

1.00 point

III d. For:

the refraction law on the AD face sini1 =n1 ⋅ sinr1 0.25p

Figure III.2 the refraction law on the AC face n1 ⋅ sinr1 ' =n2 ⋅ sinr2

0.25p

1 1

1 r ' A

r + =

0.25p

2

2 A

r =

0.25p

°

=30

1

i

0.25p

1

1 2

2 2

1

sin

cos sin

2 1 4

A

A A

n

=

−

2.75 points

IPhO 1983 Theoretical Question III

Professor Delia DAVIDESCU, National Department of Evaluation and Examination– Ministry of Education and

Research- Bucharest, Romania

Professor Adrian S.DAFINEI,PhD, Faculty of Physics – University of Bucharest, Romania

Marking scheme – Prisms

Page 3 of 3