CBSE Class 7 Science Light VBQs

Multiple Choice Questions:

Question. Which of the following does not show reflection of light?
a) Plane mirror
b) Concave mirror
c) Convex mirror
d) Card board
Answer : D

Question. Which is used for rear view in cars and other vehicles?
a) Concave mirror
b) Convex mirror
c) Convex lens
d) Concave lens
Answer : B

Question. The image of an object formed by a concave lens is always:
a) Real and diminished
b) Virtual and larger
c) Real and larger
d) Virtual and diminished
Answer : D

Question. The process of splitting of white light in seven colours on passing through a prism is called:
a) Reflection of light
b) Refraction of light
c) Bending of light
d) Dispersion of light
Answer : D

Fill In The Blanks.

(i). An image formed by a plane mirror is always of the same size as that of object.

(ii). In a plane mirror, the left hand of a person appears to be the right hand in the image and right hand appears to be the left hand in the image.

(iii). The image formed by a convex mirror is always virtual and smaller in size.

(iv). Convex lenses are thicker in the middle and concave lenses are thinner in the middle than at the edges.

(v). A prism splits the white light into seven (7) colours.

Write True Or False.

Question. There is reflection of light through a lens.  
Answer : False

Question. The ray of light coming towards the plane mirror is called the reflected ray. 
Answer : False

Question. The image formed by a plane mirror is always in front of the mirror. 
Answer : False

Question. A concave mirror is a part of hollow sphere of glass, whose outer side is coated with silver layer and reflection takes place from the inside.  
Answer : True

Question. Concave lens always forms a virtual, erect and smaller image of the object. 
Answer : True

ACTIVITY- Reflection through a mirror.

Question. The process of change in direction of light after falling on a mirror is called …… of light.
Answer : Reflection.

Question. Angle of incidence is equal to angle of reflection. (True/False)
Answer : True.

ACTIVITY- To obtain the image of an object on a screen using a concave mirror. 

Question. When the object is very far from the concave mirror, the image formed is ……. and ………
Answer : Small and inverted.

Question. The image formed on the screen is real. (True/False)
Answer : True.

Question. For a concave mirror, the image formed is always real. (True/False)
Answer : False.

ACTIVITY- The distance of the object in front of the mirror is same as the distance of the image behind the mirror.

Question. The distance between the object and the mirror is ……. to the distance between the image and the mirror.
Answer : Equal.

Question. The plane mirror has to be placed vertically on the graph paper. (True/False)
Answer : True.

Question. The plane mirror should be vertically upright. (True/False)
Answer : True.

ACTIVITY- To obtain the image of the sun on a wall using a concave mirror. 

Question. The image of the sun formed by the concave mirror on the wall is …….. image.
Answer : Real.

Question. Is the image of a candle seen using a concave mirror same as that of the Sun seen on the wall?
Answer : Yes (both are real).

ACTIVITY-To study the formation of white light by mixing seven colours.

Question. White light is composed of …………. colours.
Answer : Seven (7).

Question. When disc with seven colours is rotated, it appears to be red.. (True/False)
Answer : False.

Question. Name the seven colours of which the white light is made off.
Answer : VIBGYOR- Violet, Indigo, Blue, Green, Yellow, Orange and Red.

ACTIVITY- To obtain the image of the sun on a paper using a convex lens.

Question. The bright spot of light obtained on the paper is the image formed of the ………..
Answer : Sun.

Question. Image obtained on the paper is the virtual image. (True/False)
Answer : False.

ACTIVITY-  To obtain the image of an object on a screen using a convex lens.

Question. The convex lens is placed between the object and the screen. (True/False)
Answer : True.

Question. For a convex lens, image formed is always real. (True/False)
Answer : False.

Match The Column ‘A’ With Column ‘B’.

Answer : (i) - (d), (ii) - (c), (iii) - (b), (iv) - (a), 

Very Short Answer Type Questions.

Question. Which optical instrument uses convex lens?
Answer : Microscope.

Question. Is the image formed by a plane mirror real or virtual?
Answer : Virtual.

Question. What is the seven rainbow coloured disc called?
Answer : Newton disc.

Question. Which lens forms a real image of an object?
Answer : Convex lens.

Short Answer Type Questions.

Question. Differentiate between real and virtual images. Give examples.
Answer : 

Question. A person is standing 5m away from a plane mirror. How far will his image be:
(1) From the mirror, (2) From the person himself?
Answer : (1) From the mirror – 5m, (2) From the person himself – 10m.

Question. Ravi is observing his image in a plane mirror. The distance between the mirror and his image is 6m.
If he moves 2m towards the mirror, then the distance between Ravi and his image will be:
Answer : 8m.

Question. State two differences between convex lens and concave lens.
Answer :

Question. Give two uses of concave mirror.
Answer : Concave mirrors are used in vehicle’s headlights, by ENT doctor and in solar furnaces.

Question. Of how many colours is white light made off? Name them.
Answer : Seven (7). VIBGYOR- Violet, Indigo, Blue, Green, Yellow, Orange and Red.

Long Answer Type Questions.

Question. What is meant by dispersion of light? Explain by using a prism. Which natural phenomenon is associated with dispersion of light?
Answer : Dispersion of light- The process of splitting of white light in seven colours on passing through a prism is called dispersion of light.
When we pass white light through a prism, we see that it splits into seven colours i.e.
VIBGYOR- Violet, Indigo, Blue, Green, Yellow, Orange and Red. Rainbow formed in the sky after raining is due to dispersion of light.

Question. State and explain the characteristics of the image formed by a plane mirror.
Answer : Characteristics of the image formed by a plane mirror-
(1) Plane mirror forms an erect and virtual, image.
(2) Plane mirror forms laterally inverted image.
(3) Plane mirror forms image behind the mirror.
(4) Plane mirror forms the same size image as that of object.
(5) Plane mirror forms image at the same distance from the mirror as the object is in front of it.