Physics - Light

Which of the following can make a parallel beam of light when light from a point source is incident on it?

• Concave mirror as well as convex lens

• Convex mirror as well as concave lens

• Two plane mirrors placed at 90° to each other

• Concave mirror as well as concave lens

A 10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. The focal length of this mirror is

• -30cm

• -20cm

• -40cm

• -60cm

Under which of the following conditions a concave mirror can form an image larger than the actual object?

• When the object is kept at a distance equal to its radius of curvature

• When object is kept at a distance less than its focal length

• When object is placed between the focus and centre of curvature

• When object is kept at a distance greater than its radius of curvature

A light ray enters from medium A to medium B as shown in figure. The refractive index of medium B relative to A will be

• Greater than Unity

• Less than Unity

• Equal to Unity

• Zero

Magnification produced by a rear view mirror fitted in vehicles Is

• Less than one

• More than one

• Equal to one

• can be more than or less than one depending upon the position of the object in front of it.

Rays from Sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object?

• 15 cm in front of the mirror

• 30 cm in front of the mirror

• between 15 cm and and 30 cm in front of the mirror

• more than 30 cm in front of the mirror

A full length image of a distant tall building can definitely be seen by using

• Concave mirror

• Convex mirror

• Plane mirror

• both concave as well as plane mirror

In torches, search lights and headlights of vehicles the bulb is placed

• between the pole and the focus of the reflector

• very near to the focus of the reflector

• between the focus and centre of curvature of the reflector

• at the centre of curvature of the reflector

The laws of reflection hold good for

• plane mirror only

• concave mirror only

• convex mirror only

• all mirrors irrespective of their shape

You are given water, mustard oil, glycerine and kerosene. In which of these media a ray of light incident obliquely at same angle would bend the most?

• Kerosene

• Water

• Mustard Oil

• Glycerine