Lakhmir Singh and Manjit Kaur Solutions for Chapter: Refraction of Light, Exercise 34: Multiple Choice Questions (MCQs)

The focal length of four convex lenses $P, Q, R$ and $S$ are $20 \mathrm{cm}, 15 \mathrm{cm}, 5 \mathrm{cm}$ and $10 \mathrm{cm}$, respectively. The lens having greatest power is:

A converging lens has a focal length of $50 \mathrm{cm}$. The power of this lens will be:

A diverging lens has a focal length of $0.10 \mathrm{m}$. The power of this lens will be:

The power of a lens is $+2.0 \mathrm{D}$. Its focal length should be:

If a spherical lens has a power of, $-0.25 \mathrm{D}$, the focal length of this lens will be:

The power of a concave lens is $10 \mathrm{D}$ and that of a convex lens is $6 \mathrm{D}$. When these two lenses are placed in contact with each other, the power of their combination will be:

The power of a converging lens is $4.5 \mathrm{D}$ and that of a diverging lens is $3 \mathrm{D}$. The power of this combination of lenses placed close together is:

A convex lens of focal length $10 \mathrm{cm}$ is placed in contact with a concave lens of focal length $20 \mathrm{cm}$. The focal length of this combination of lenses will be: