Light, Shadows and Reflection: 21 MCQs with answers

A form of energy that travels in straight lines

Light is a form of energy that travels in straight lines called rays. It is not matter, sound, or magnetism.

An opaque object

An opaque object blocks light completely, forming a dark, clear shadow. Transparent objects cast no shadow, and translucent objects cast only a faint one.

Clear glass

Clear glass is transparent, so almost all light passes through it and no shadow is formed. Wood and metal are opaque; frosted glass is translucent.

The shadow becomes larger

When the object is closer to the light source, it blocks a wider cone of rays, producing a larger shadow.

A point source like a small bulb

A point source (small bulb) gives a sharp shadow, while an extended source (long tube light) gives a blurry shadow with a darker middle and lighter edges.

The bouncing back of light from a surface

Reflection is the bouncing back of light from a surface. Absorption, bending, and blocking are different phenomena.

A smooth, polished mirror

Regular reflection occurs on smooth, polished surfaces like mirrors and forms clear images. Rough surfaces cause diffuse reflection.

Equal to the angle of reflection

The first law of reflection states that the angle of incidence is always equal to the angle of reflection.

True

The angle of incidence is always equal to the angle of reflection, and the incident ray, reflected ray, and normal lie in the same plane.

The image raises the hand on its left side

A plane mirror produces lateral inversion — left and right are swapped. So when the student raises her right hand, the image appears to raise the hand on its left side.

The image is inverted (upside down)

A plane mirror forms a virtual, erect, same-sized, laterally inverted image. It does not turn the image upside down.

Scattered in many directions by diffuse reflection

The rough surface of the paper causes diffuse reflection, scattering light in all directions so the page is visible from any angle.

A non-luminous object that reflects sunlight

The Moon is non-luminous — it does not emit its own light. We see it because it reflects sunlight.

The Moon's shadow falls on the Earth

A solar eclipse occurs when the Moon comes between the Sun and the Earth, and the Moon's shadow falls on the Earth.

Solar cooker and periscope

Solar cookers use mirrors to concentrate sunlight, and periscopes use two mirrors to reflect light. Both work on the principle of reflection.

A faint shadow

Frosted glass is translucent — it allows some light to pass through, so a faint shadow is formed on the wall.

The shadow grows larger and less defined.

When the object is moved closer to the light source, it blocks a wider cone of light rays, resulting in a larger shadow that is less defined due to the spreading of light rays.

6 meters

The image formed by a plane mirror appears the same distance behind the mirror as the object is in front of it. Therefore, if the object is 3 meters away, the image will also appear 3 meters behind the mirror, totaling 6 meters from the object.

The shadow will become larger and blurrier.

Switching to an extended light source causes the shadow to become larger and blurrier because the rays of light spread out more, leading to less defined edges.

The shadow will be faint and less defined.

A frosted glass sheet is translucent, allowing some light to pass through, which results in a faint and less defined shadow compared to an opaque object that blocks all light.

The angle of reflection will be 30 degrees, producing a clear image.

According to the law of reflection, the angle of reflection equals the angle of incidence. Thus, if the angle of incidence is 30 degrees, the angle of reflection will also be 30 degrees, resulting in a clear image due to regular reflection.