Ch-10 Light - Reflection and Refraction (Question) Page168

Question 1:	Define the principal focus of a concave mirror.
Answer :	Light rays that are parallel to the principal axis of a concave mirror converge at a specific point on its principal axis after reflecting from the mirror. This point is known as the principal focus of the concave mirror.
Question 2:	The radius of curvature of a spherical mirror is 20 cm. What is its focal length?
Answer :	Radius of curvature, R = 20 cm Radius of curvature of a spherical mirror = 2 × Focal length (f) R = 2f Hence, the focal length of the given spherical mirror is 10 cm.
Question 3:	Name the mirror that can give an erect and enlarged image of an object.
Answer :	When an object is placed between the pole and the principal focus of aconcave mirror, the image formed is virtual, erect, and enlarged.
Question 4:	Why do we prefer a convex mirror as a rear-view mirror in vehicles?
Answer :	Convex mirrors give a virtual, erect, and diminished image of the objects placed in front of them. They are preferred as a rear-view mirror in vehicles because they give a wider field of view, which allows the driver to see most of the traffic behind him.