CBSE NCERT Solutions for Class 7 Science Chapter 15

The CBSE NCERT Solutions for all the subjects for class 7 will help you in preparing for exams, solving homework questions or learning concepts as well. The solutions are provided by Edurite’s subject experts in a step-by-step fashion for each chapter in all the subjects.

CBSE NCERT Solutions for Class 7 Science Chapter 15:

Question-1:

Mark T if the statement is true and F if it is false:
(a) We can obtain an enlarged and erect image by a convex mirror. (T/F)
(b) A concave lens always form a virtual image. (T/F)
(c) We can obtain a real, enlarged and inverted image by a concave mirror. (T/F)
(d) A real image cannot be obtained on a screen. (T/F)
(e) A concave mirror always form a real image. (T/F)

Solution:

(a) F (b) T (c) T (d) F (e) F

Question-2:

State the characteristics of the image formed by a plane mirror.

Solution:

Characteristics of the image formed by a plane mirror:
(i) The image formed is virtual
(ii) The image is laterally inverted.
(iii) It is of the same size as the object.
(iv) The image is situated at the same distance from the mirror as the object.
(v) The image is erected.

Question-3:

What is a virtual image? Give one situation where a virtual image is formed.

Solution:

The image which cannot be formed or obtained on the screen is called virtual
image. When we stand in front of our dressing table mirror, we use to see our virtual image. The virtual image is formed in case of plane and convex mirror.

Question-4:

The rear view mirror of a car is a plane mirror. A driver is reversing his car at
a speed of 2 m/s. The driver sees in his rear view mirror the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be
(i) 1 m/s (ii) 2 m/s
(iii) 4 m/s (iv) 8 m/s

Solution:

(iii) 4 m/s
In case of plane mirror, the distance is always doubled therefore the speed is in case between the image and the object. So, when driver is reversing his car at a speed of 2 m/s, then the image is also coming closer to the mirror by 2m/s. Thus, it seems that the image of the truck appears to approach the driver at 4 m/s.