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
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IPhO 1983
Theoretical Question III
Marking scheme – Prisms
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Part MARKING SCHEME - THE THEORETICAL QUESTION III - PRISMS Total
Scores
III. a.
For:
( ) ( )
0201
λλ
nn
=
0.50p
12
21
0
aa
bb
−
−
=
λ
0.25p
final result:

nm500
0
=
λ
0.25p

( ) ( )
5,1
0201
==
λλ
nn
0.25p
1.25 points
III. b.
For the rays with different wavelength (
ioletred v
λλλ
,,
0
) 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
'
sin
min
0201
A
A
nn
+
==
δ
λλ
0.25p
( )
°=
30'
ˆ
Am
0.25p
2
'
2
'
sin
2
3
arcsin2
min
AA
−







⋅=
δ
0.25p
final result:
°≅
7,30
min
δ
0.25p
1.00 point
III. d.
For:
the refraction law on the
AD
face
111
sinsin rni
⋅=
0.25p
Figure III.2
the refraction law on the
AC
face
2211

sin'sin rnrn
⋅=⋅

0.25p
111
' Arr
=+

0.25p
22
Ar
=

0.25p
°=
30
1
i

0.25p
1
122
2
1
sin
cossin2
14
A
AAn
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
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