Light (Reflection&Refraction)

1. An object is placed at a distance of 0.25 m in front of a plane mirror. The distance between the object and image will be.

• 0.25m

• 1.0m

• 0.5m

• 0.125m

An object at a distance of 30 cm from a concave mirror gets its image at the same point. The focal length of the mirror is

• -30cm

• 30cm

• -15cm

• 15cm

The angle between incident ray and refracted ray on plane mirror is 70⁰ ,the angle of incident is

• 70⁰

• 35⁰

• 30⁰

• 20⁰

A concave mirror of focal length 20 cm forms an image having twice the size of object. For the virtual position of object, the position of object will be at

• 25cm

• 10cm

• 40cm

• 20cm

. If a man’s face is 25 cm in front of concave shaving mirror producing erect image 1.5 times the size of face, focal length of the mirror would be

• 75cm

• 25cm

• 150cm

• 50cm

As light travels from a rarer to a denser medium it will have

• increased velocity

• decreased velocity

• No change in velocity

• Non of the adove

The angle of incidence i and refraction r are equal in a transparent slab when the value of i is

• 0⁰

• 90⁰

• 45⁰

• 60⁰

The refractive index of transparent medium is greater than one because

• Speed of light in vacuum < speed of light in tansparent medium

• Speed of light in vacuum > speed of light in tansparent medium

• Speed flight in vacuum = speed of light in tansparent medium

• Frequency of light wave changes when it moves from rarer to denser medium

The refractive index of glass is 1.5. The speed of light in glass will be ( speed of light in free space is 3x10⁸m/s.)

• 2x10⁸m/s

• 3.5x10⁸m/s

• 4.5x10⁸m/s

• 2.25x10⁸m/s

You are given three media A, B and C of refractive index 1.43, 1.25 and 1.6. The medium in which the light will travel fastest is

• A

• B

• C

• Equal in all three medium