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## 20 Questions MCQ Test Science Class 6 | Olympiad Test: Light, Shadows & Reflections

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QUESTION: 1

### The diagram shows an object O viewed using two mirrors. A person looks into the mirrors as shown. At which position is the image of O seen?

Solution:

Explanation : Answer is 'D' as the eye can see the image on the first mirror as light will reflect from the second mirror at an angle that it hits the first mirror and then the eye

QUESTION: 2

### When Abhishek looked at a lighted torch through an object he could see a faint glow, but not the torch. The object is

Solution:

Translucent objects allow only a small part of light to pass through them.

QUESTION: 3

### Which of the following explains why air is not visible?

Solution:

Air is transparent because air contains so few atoms, light waves run into very few of them when they shine through air. The molecules of air are smaller than the wavelength of the light. Due to this reason, particles of air weakly interact with visible light and reflect little or no light to our eyes.
Transparent material allows all the light to pass through it. In other words transmission is the property of light to permit the passage of light with some or none of the incident light being absorbed or scattered in the process. Since, air is transparent, it transmits almost whole of light.

QUESTION: 4

A girl is 4 m away from the plane mirror. If she moves few steps closer to the mirror, what will happen to the image size in the mirror?

Solution:

The image formed in the plane mirror is always of the same size as that of the object.

QUESTION: 5

A plane mirror reflects a pencil of light to form a real image. Then the pencil of light incident on the mirror is

Solution:

When at convergence point O, a convergent beam of light is incident on the plane mirror, a real image is formed at the point I.

QUESTION: 6

Study the set-up below.

How will the shadow look like?

Solution:

Book is an opaque object and hence does not allow the light of torch to pass through it. As there is no light on the ring, hence no image will be formed and the screen will remain dark due to absence of any light ray.

QUESTION: 7

There is no dark shadow formed by the glass when light is shone on it. This is because

Solution:

The shadows are formed when the opaque object cuts off the light from the source. Since glass is transparent, it allows the light to pass through it. So no dark shadow is formed.

QUESTION: 8

Which of the following statements is true?

Solution:

Light changes its direction after reflection. As we move the object away from the light source, the shadow becomes larger as the distance between object and the light source increases. Reflection is possible from rough surface also.

QUESTION: 9

Fill in the blanks with most appropriate option. Although a number of objects, such as kites, birds, aeroplanes move in space, but their shadow is not seen on the earth. This is due to the reason that the

(i), the region of complete (ii) is not able to reach the earth. The region of partial (iii), that is the (iv) reaching the earth is too large and too faint to be visible to us.

Solution:
QUESTION: 10

Which of the items above will allow you to see around a corner from where you are standing?

Solution:

Figure (iii) is periscope which is used to see around the corners. It is based upon the principle of rectilinear propagation of light and reflection of light.

QUESTION: 11

You are standing upright in a room in front of a vertical mirror. In this mirror, you can see from your position, only the upper two- third part of your body. You wish to see the full image of your body in the mirror. Which combination of the following three courses of action will achieve this?
I. Move away from the mirror
II. Move towards the mirror
III. Use a mirror whose height will allow you to see your full image

Solution:

To see the entire length of your body reflected in the mirror, you should use a mirror whose height will allow you to see your full image.

QUESTION: 12

The mirror image of TRANSPARENT will be

Solution:
QUESTION: 13

Vijay puts some water into four cups made of steel, porcelain, glass, frosted glass. Which one of these cups will allow him to see the level of the water clearly?

Solution:

Glass is a transparent material. It allows light to pass through it.

QUESTION: 14

Three sticks are placed in an open field as shown in figure. Which of the following sticks will form the shadow of equal length?

Solution:

The length of the shadow changes according to the position of the source of light, i.e., the sun with respect to the object.

QUESTION: 15

Nisha placed a stick in the playground at 8:15 am in the morning. How will the shadow of the stick at 12:00 noon be in comparison to the one at 8:15 am?

Solution:

Shadow formed is larger in the morning and evening as compare to the shadow at noon because at noon the sun is at top of the stick.

QUESTION: 16

Look at the Venn diagram. Which of the following objects described below are most likely to be I, II and III? Choose the correct option.

Solution:
QUESTION: 17

A solid transparent sphere has a small opaque dot at its centre. When observed from outside, the apparent position of the dot will be

Solution:

As u =

⇒ v = −R

QUESTION: 18

Geeta placed three objects made of different materials as shown in the figure. She observed a bright spot of light at (II) but (III) would not get any spot.-Then,

Solution:

Transparent material allows light to pass through it and opaque object obstructs it.

QUESTION: 19

Riya and Priya were sitting around a round table. They noticed that they could see their own and each other's image onto the table top. Then table top is made of

Solution:

Polished glass of red colour reflects some of the light incident on it so images of the both persons are formed on it.

QUESTION: 20

Read the given statements and select the correct option,
Statement 1: Rahul placed a colored plastic bottle in front of the beam of a torch light. Then he placed a transparent sheet of same size on the other side of bottle. No shadow will form on the screen.
Statement 2: Translucent objects allow light to pass through them partially.

Solution:

A colored plastic bottle is an opaque material. When a light beam is incident on it, a shadow will form on the screen can easily pass through the transparent material.