Light Reflection and Refraction

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

• (a) 0.25 m

• (b) 1.0 m

• (c) 0.5 m

• (d) 0.125 m

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

• (a) – 30 cm

• (b) 30 cm

• (c) – 15 cm

• (d) +15 cm

An object at a distance of + 15 cm is slowly moved towards the pole of a convex mirror. The image will get

• (a) shortened and real

• (b) enlarged and real

• (c) enlarge and virtual

• (d) diminished and virtual

A concave mirror of radius 30 cm is placed in water. It’s focal length in air and water differ by

• (a) 15

• (b) 20

• (c) 30

• (d) 0

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

• (a) 25 cm

• (b) 40 cm

• (c) 10 cm

• (d) At infinity

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

• (a) 75 cm

• (b) 25 cm

• (c) 15 cm

• (d) 60 cm

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

• (a) increased velocity

• (b) decreased velocity

• (c) decreased wavelength

• (d) both (b) and (c)

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

• (a) 0°

• (b) 45°

• (c) 90°

• (d) depend on the material of the slab

The refractive index of water is 1.33. The speed of light in water will be

• (a) 1.33 × 10^8 m/s

• (b) 3 × 10^8 m/s

• (c) 2.26 × 10^8 m/s

• (d) 2.66 × 10^8 m/s

An object is placed 60 cm in front of a concave mirror. The real image formed by the mirror is located 30 cm in front of the mirror. What is the object’s magnification?

• (a) +2

• (b) -2

• (c) +0 5.

• (d) -0 5