Chapter 13, Problem 31R

To determine

Image formation by lenses and mirrors.

Explanation of Solution

Introduction:

Mirrors:

• When a curved surface is painted outside and the inside part is kept reflecting, then it is called as concave mirror. It is also called a converging mirror.
• When a curved surface is painted from the inside and kept reflecting on the outside, then it is called as convex mirror. It is also known as diverging mirror.

Lenses:

• A concave lens is thinner at the inside and thicker at the outer ends of the lens. It is called a diverging lens.
• A convex lens is thicker at the inside and thinner at the outer ends of the lens. It is called as converging lens.

Image formation by lenses and mirrors:

Type of lens or mirror	Position of object	Type of image
Concave lens	All positions of object	Virtual, upright and reduced
Convex lens	Closer than one focal length	a. virtual, upright, enlarged
Between one and two focal lengths	b. real, inverted, enlarged
Farther than two focal lengths	real, inverted, reduced
Concave mirror	Closer than one focal length	c. virtual, upright, enlarged
Object placed at focal point	d. real, inverted, enlarged
Farther than two focal lengths	e. real, inverted, reduced
Convex mirror	All positions of object	f. virtual, upright, reduced

Conclusion:

Hence, the image formation is different for different types of mirrors and lenses.