Light Energy Test - 6

According to the question the correct option will be ‘B’ because the speed at which the light travels in vacuum is \(3 \times 10^{8} \mathrm{m} / \mathrm{s}\).

Visible light is a range of wavelengths in the electromagnetic spectrum between infrared and ultraviolet for which we have the capability to visually detect. So, light is a form of energy that we detect with our eyes.

According to the question the correct option will be ‘A’ because When we put any object in between the light source it forms a shadow of that object. The closer the object is to the source of the light, the more light it blocks out, so its shadow is bigger. But if the object is further away, it does not block out much light, and so the shadow is smaller.
Therefore, for the shadow of the ceiling fan to be formed on a wall opposite to the door, the electric bulb must be positioned on the wall having the door.

According to the question the correct option will be ‘B’ because a concave lens is thicker at the edges than in the middle whereas convex lens is thicker in the middle than at the edges. Concave lens spreads light rays apart producing an image smaller than the actual object.

According to the question the correct option will be ‘A’ because

Imagine you are standing in front of a mirror and moves x units away from the mirror, so you can see that your image also moves away from the mirror by x units. i.e. 2x units away from you.

So both move in equal time duration, same can be said for velocities.

Therefore image velocity with respect to object will be 2v.

According to the question the correct option will be ‘D’ because all the three statements are true that light is observed when switching on the torch, sunlight is observed in early morning and a beam of light can be observed through a hole.

According to the question the correct option will be ‘B’ because candle, sun and bulb emit light radiation when they glow, so they are the sources of light. But black body do not emit light and thus is is not a source of light.

We see an object because of reflection. Light gets reflected from the object and reach our eyes and thus we can see the object. So, we have to light a torch on the object, not on our eyes.

According to the question the correct option will be ‘C’ because A light ray is a narrow beam of light that is moving in a defined direction. Alternatively, a beam of light consists of lot of light rays parallel to each other.

Moon is a non luminous body. It is visible due to the light falling on it. It reflects the light.

A yellow colour dress would reflect only yellow colour and a green filter will allow only green colour to pass. So, no colour will pass through the filter and hence the dress will appear black.

A beam of light is group of rays of light travelling in a particular direction. 

A ray of light is the direction along which the light energy propagates.

Hence, the correct answer is option A.

According to the question the correct option will be ‘A’ because Ray light is defined as each of the lines in which light (and heat) may seem to stream from the sun or any luminous body, or pass through a small opening.

Objects which allow the light to pass through them completely without any obstruction are called transparent objects.

Objects which allow the light to pass through them partially are called translucent objects.

Objects which do not allow the light to pass through them are called opaque objects.

Since, a diamond allows the light to pass through it completely without any absorption or obstruction of light, it is a transparent object.

Hence, the correct answer is option A.

According to the question the correct option will be ‘B’ because when the rays of light starting from a point travel in different directions, then the collection of such rays is termed as a divergent beam of light.