Lakhmir Singh and Manjit Kaur Solutions for Chapter: Refraction of Light, Exercise 32: Short Answer Type Questions

A convex lens of focal length $25 \mathrm{cm}$ and a concave lens of focal length $10 \mathrm{cm}$ are placed in close contact with one another.

What is the power of this combination?

A convex lens of focal length $25 \mathrm{cm}$ and a concave lens of focal length $10 \mathrm{cm}$ are placed in close contact with one another.

What is the focal length of this combination?

A convex lens of focal length $25 \mathrm{cm}$ and a concave lens of focal length $10 \mathrm{cm}$ are placed in close contact with one another.

Is this combination converging or diverging?

The power of a combination of two lenses $X$ and $Y$ is $5 \mathrm{D}$. If the focal length of lens $X$ be $15 \mathrm{cm}$:

Calculate the focal length of the lens $Y$.

The power of a combination of two lenses $X$ and $Y$ is $5 \mathrm{D}$. If the focal length of lens $X$ be $15 \mathrm{cm}$:

State the nature of lens $Y$.

Two lenses $A$ and $B$ have focal lengths of $+20 \mathrm{cm}$ and, $-10 \mathrm{cm}$, respectively:

What is the nature of lens $A$ and lens $B$?

Two lenses $A$ and $B$ have focal lengths of $+20 \mathrm{cm}$ and, $-10 \mathrm{cm}$, respectively:

What is the power of lens $A$ and lens $B$?

Two lenses $A$ and $B$ have focal lengths of $+20 \mathrm{cm}$ and, $-10 \mathrm{cm}$, respectively:

What is the power of the combination if lenses $A$ and $B$ are held close together?