Physics Quiz on Optics and Electricity

Focal length of a concave mirror is 20 cm. Object is placed at 40 cm. The image is formed at:

• 20 cm

• 30 cm

• 40 cm

• 60 cm

Power of a convex lens of focal length 0.25 m is:

• 2 D

• 3 D

• 4 D

• 5 D

A parallel beam of light after reflection from a concave mirror passes through:

• Pole

• Focus

• Centre of curvature

• Principal axis

Refractive index of water is 4/3. If speed of light in vacuum is 3 × 10⁸ m/s, speed in water is:

• 2.25 × 10⁸ m/s

• 2 × 10⁸ m/s

• 2.5 × 10⁸ m/s

• 3 × 10⁸ m/s

A ray passing through the optical centre of a convex lens:

• Deviates towards axis

• Deviates away

• Passes undeviated

• Totally reflects

Which lens is used to correct hypermetropia?

• Concave

• Convex

• Cylindrical

• Plano-concave

The mirror used in vehicles as rear-view mirror is:

• Concave

• Convex

• Plane

• Cylindrical

When light passes from rarer to denser medium:

• Bends towards normal

• Away from normal

• Does not bend

• Totally reflects

Magnification produced by plane mirror is:

• Zero

• Less than 1

• 1

• More than 1

If object is at focus of concave mirror, image is formed at:

• Pole

• Infinity

• Centre of curvature

• Behind mirror