NCERT Class X Science Solutions: Chapter 10 – Light, Reflection and Refraction Part 1

Get top class preparation for CBSE/Class-9 Science right from your home: fully solved questions with step-by-step explanation- practice your way to success.

Download PDF of This Page (Size: 162K)

Question 1:

Which one of the following materials cannot be used to make a lens?

  1. Water

  2. Glass

  3. Plastic

  4. Clay

Answer:

A lens allows light to pass through it. Since clay does not show such property, it cannot be used to make a lens.

Because clay is not transparent or translucent to the kind of light we can see.

Question 2:

The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?

  1. Between the principal focus and the centre of curvature

  2. At the centre of curvature

  3. Beyond the centre of curvature

  4. Between the pole of the mirror and its principal focus.

Answer:

D. When an object is placed between the pole and principal focus of a concave mirror, the image formed is virtual, erect, and larger than the object.

Question 3:

Where should an object be placed in front of a convex lens to get a real image of the size of the object?

  1. At the principal focus of the lens

  2. At twice the focal length

  3. At infinity

  4. Between the optical centre of the lens and its principal focus.

Answer:

B. When an object is placed at the centre of curvature in front of a convex lens, its image is formed at the centre of curvature on the other side of the lens. The image formed is real, inverted, and of the same size as the object.

Question 4:

A spherical mirror and a thin spherical lens have each a focal length of −15 cm. The mirror and the lens are likely to be

  1. both concave

  2. both convex

  3. the mirror is concave and the lens is convex

  4. the mirror is convex, but the lens is concave

Answer:

By convention, the focal length of a concave mirror and a concave lens are taken as negative. Hence, both the spherical mirror and the thin spherical lens are concave in nature.

Question 5:

No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be

  1. Plane

  2. Concave

  3. Convex

  4. either plane or convex

Answer: D

A convex mirror always gives a virtual and erect image of smaller size of the object placed in front of it. Similarly, a plane mirror will always give a virtual and erect image of same size as that of the object placed in front of it. Therefore, the given mirror could be either plane or convex.

Result for Convex mirror.

Convex Mirror

Developed by: