The picture shows the size of the pupil under two different conditions. What makes the pupil change size between condictions 1 and 2?

When the amount of light entering the eye is reduced, such as in a dimly lit room, the pupil dilates or becomes larger to allow more light to enter the eye. This is controlled by the muscles in the iris, which contract to increase the size of the pupil. On the other hand, when the amount of light entering the eye is increased, such as in bright sunlight, the pupil constricts or becomes smaller to reduce the amount of light entering the eye. This is also controlled by the muscles in the iris, which relax to decrease the size of the pupil.

Two plane mirrors are arranged perpendicular to each other. If a light ray is incident at 30 ∘ on one of the plane mirrors of above arrangement, then find the angle of reflection at the second plane mirror.

According to the laws of reflection, the light ray will get reflected at an angle of 30 ∘ as it is incident at an angle of incidence equal to 30 ∘ . Hence, the glancing angle at the other perpendicular mirror will be 30 ∘ . The angle of incidence and the angle of reflection on the second mirror will be 90 ∘ - 30 ∘ = 60 ∘ . The ray diagram is shown below.

Two plane mirrors are arranged perpendicular to each other. If a light ray is incident at 30 ∘ on one of the plane mirrors of the above arrangement, then find the angle of deviation for both the mirrors.

According to the laws of reflection, the light ray will get reflected at an angle of 30 ∘ as it is incident at an angle of incidence equal to 30 ∘ . Hence, the glancing angle at the other perpendicular mirror will be 30 ∘ . The angle of incidence and the angle of reflection on the second mirror will be 90 ∘ - 30 ∘ = 60 ∘ . The ray diagram is shown below. We know that the angle of deviation is equal to two times of the glancing angle. Hence, the angle of deviation for the first mirror will be 120 ∘ and the angle of deviation for the second mirror will be 60 ∘ .

E M B I B E

Science Textbook of Competency Based Questions for Class VIII>Chapter 13 - Light>Exercise

NCERT Solutions for Chapter: Light, Exercise 1: Exercise

Author:NCERT

NCERT Science Solutions for Exercise - NCERT Solutions for Chapter: Light, Exercise 1: Exercise

Attempt the practice questions on Chapter 16: Light, Exercise 1: Exercise with hints and solutions to strengthen your understanding. Science Textbook of Competency Based Questions for Class VIII solutions are prepared by Experienced Embibe Experts.

Questions from NCERT Solutions for Chapter: Light, Exercise 1: Exercise with Hints & Solutions

EASY

8th CBSE

IMPORTANT

Science Textbook of Competency Based Questions for Class VIII>Chapter 13 - Light>Exercise>Q 6

Which of these objects reflects light?

EASY

8th CBSE

IMPORTANT

Science Textbook of Competency Based Questions for Class VIII>Chapter 13 - Light>Exercise>Q 7

The diagram shows the basic parts of human eye.

Question Image

Which part protects the human eye from injury?

MEDIUM

8th CBSE

IMPORTANT

Science Textbook of Competency Based Questions for Class VIII>Chapter 13 - Light>Exercise>Q 8

The picture shows the size of the pupil under two different conditions.

Question Image

What makes the pupil change size between condictions 1 and 2?

MEDIUM

8th CBSE

IMPORTANT

Science Textbook of Competency Based Questions for Class VIII>Chapter 13 - Light>Exercise>Q 14

A person with a myopic eye, cannot see objects beyond $1.2 m$ distinctly. What can be said about the likely size of his eyeball ? State the nature of corrective lens needed to restore his proper vision ?

MEDIUM

8th CBSE

IMPORTANT

Science Textbook of Competency Based Questions for Class VIII>Chapter 13 - Light>Exercise>Q 19

Two plane mirrors are arranged perpendicular to each other. If a light ray is incident at $30^{\circ}$ on one of the plane mirrors of above arrangement, then find the angle of reflection at the second plane mirror.

MEDIUM

8th CBSE

IMPORTANT

Science Textbook of Competency Based Questions for Class VIII>Chapter 13 - Light>Exercise>Q 66

Calculate the angle between two mirrors if four images are formed by placing a book in between the two plane mirrors.

MEDIUM

8th CBSE

IMPORTANT

Science Textbook of Competency Based Questions for Class VIII>Chapter 13 - Light>Exercise>Q 83

Jim determined the number of images formed by two plane mirrors inclined at certain angle from a ray diagram shown below. Can you determine the number of images formed by two plane mirrors in the arrange ment shown below?

Question Image

MEDIUM

8th CBSE

IMPORTANT

Science Textbook of Competency Based Questions for Class VIII>Chapter 13 - Light>Exercise>Q 90

Two plane mirrors are arranged perpendicular to each other. If a light ray is incident at $30^{\circ}$ on one of the plane mirrors of the above arrangement, then find the angle of deviation for both the mirrors.

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