# Light Reflection and Refraction Worksheet

## QUESTIONS: (1 mark each)

Question 1.
Define the principal focus of a concave mirror.
Question 2.
Which mirror is used by dentists?
Question 3.
What are the advantages and disadvantages of using convex mirror for seeing traffic at the rear?
Question 4.
What are the advantages and disadvantages of using a convex mirror for seeing traffic at the rear?
Question 5.
The refractive index of diamond is 2.42. What is the meaning of this statement?
Question 6.
A ray is incident along ACB on a spherical mirror, where C is the centre of curvature.
Question 7.
Find the focal length of a convex mirror whose radius of curvature is 32 cm.
Question 8.
Why do we prefer a convex mirror as a rear- view mirror in vehicles?
Question 9.
What happens when the rays of sun are focused at a point on the paper by using concave mirror?
Question 10.
How is the refractive index of an optical medium related to the speed of light in that medium?
Question 11.
Define the term absolute refractive index of a medium.

## QUESTIONS: (2 marks each)

Question 1.
Name the type of mirror used in the following situations:
ii.Side/rear view mirror of a vehicle.
iii.Solar furnace.
Question 2.
Show that the mirror formula for spherical mirrors also holds for a plane mirror too.
Question 3.
A concave mirror produces three times magnified real image of an object placed at 10 cm in front of it. Where is the image located?
Question 4.
Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is $3 \times 10^8 m/s$
Question 5.
Name the type of mirror which is known as shaving mirror. Give relevant ray diagram to justify your answer.
Question 6.
Find the focal length in cm of a lens of power -2D. Identify the type of this lens in this case.
Question 7.
Find the refractive index of glass with respect to water where refractive index of glass with respect to air is $n_{ga} = \frac {3}{2}$ and that of water with respect to air is $n_{wa} = \frac {4}{3}$.
Question 8.
A converging lens has a focal length of 250 mm. Calculate its power and express it according to sign convention.
Question 9.
List four specific characteristics of the images of the object formed by convex mirrors.
Question 10.
State two positions in which a concave mirror produces a magnified image of a given object. List two differences between the two images.
Question 11.
State the meaning of linear magnification. How is it related to object distance and image distance? When is magnification positive or negative?

### Practice Question

Question 1 Which among the following is not a base?
A) NaOH
B) $NH_4OH$
C) $C_2H_5OH$
D) KOH
Question 2 What is the minimum resistance which can be made using five resistors each of 1/2 Ohm?
A) 1/10 Ohm
B) 1/25 ohm
C) 10 ohm
D) 2 ohm
Question 3 Which of the following statement is incorrect? ?
A) For every hormone there is a gene
B) For production of every enzyme there is a gene
C) For every molecule of fat there is a gene
D) For every protein there is a gene