A student performed the experiment of glass slab and with different angles of incidence measured the angles of refraction and emergence in each case. He then recorded his observations as given in the table.

The correct observation is

S. No. Angle of incidence Angle of refraction Angle of emergence

A
B
C
D 30°
40°
50°
60° 25°
42°
50°
60° 30°
40°
50°
62°

(1) A
(2) B
(3) C
(4) D

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Solution

When a ray passes through a glass slab, it bends towards the normal. So, the angle of the incidence is always greater than the angle of refraction. The same light ray bends away from the normal and becomes parallel to the incident ray, when it emerges from the slab in the air. So, the angle of emergence is always equal to the angle of incidence. According to this, only student A has made correct observations.

Hence, the correct answer is option 1.

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Similar questions

Q. A teacher asked four students to record the observations of the experiment on tracing the path of a ray of light through a rectangular glass slab. The students recorded their observations under the following headings:
(1) Angle of incidence, Angle of refraction, Angle of reflection
(2) Angle of incidence, Angle of deviation, Angle of emergence
(3) Angle of incidence, Angle of reflection, Angle of emergence
(4) Angle of incidence, Angle of refraction, Angle of emergence
The correct observations were recorded by the student:
(1) A
(2) B
(3) C
(4) D

Q. After tracing the path of rays of light through a glass slab for three different angles of incidence, a student measured the corresponding values angle of refraction r and angle of emergence e and recorded them in the table given below:

S.No.	$∠ i$	$∠ r$	$∠ e$
I	$30^{o}$	$20^{o}$	$31^{o}$
II	$40^{o}$	$25^{o}$	$40^{o}$
III	$50^{o}$	$31^{o}$	$49^{o}$

The correct observations are:

Q. In the glass slab experiment, a student measures the angle of incidence (∠i) in air and finds it to be 40°. He also measured the corresponding angle of refraction as well as the angle of emergence for this ray of light but lost their record. The most likely record of readings for the angle of refraction and angle of emergence will be:

(1) ∠r = 40° and ∠e = 50°
(2) ∠r > 40° and ∠e = 40°
(3) ∠r = 50° and ∠e = 40°
(4) ∠r < 40° and ∠e = 40°

Q. In an experiment to study the refraction of light through a rectangular glass slab, a student measured the angle of incidence, angle of refraction and the angle of emergence. The student lost the reading of angle of incidence but noted the readings of angle of refraction to be 35° and angle of emergence to be 65°. The angle of incidence is likely to be:
(1) 45°
(2) 55°
(3) 35°
(4) 65°

After tracing the path of rays of light through a glass slab for three different angles of incidence, a student measured the corresponding values angle of refraction r and angle of emergence e and recorded them in the table given below
$\begin{matrix} S . N O & ∠ i & ∠ i & ∠ e I & 30^{\circ} & 20^{\circ} & 31^{\circ} I I & 40^{\circ} & 25^{\circ} & 40^{\circ} I I I & 50^{\circ} & 31^{\circ} & 49^{\circ} \end{matrix}$
The correct observations are

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S. No.	Angle of incidence	Angle of refraction	Angle of emergence
A B C D	30° 40° 50° 60°	25° 42° 50° 60°	30° 40° 50° 62°