all numerical of Ch 10 class 10 science book ncert
Answers
Answer:
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.
2. The radius of curvature of a spherical mirror is20 cm. What is its focal length?
Answer Radius of curvature,R= 20 cmRadius of curvature of a spherical mirror = 2 × Focal length (f)R= 2ff=R/2 = 20 / 2 = 10Hence, the focal length of the given spherical mirror is 10 cm.
3. Name the mirror that can give an erect and enlarged image of an object.
► Concave Mirror.
4. Why do we prefer a convex mirror as a rear-view mirror in vehicles?Answer-We prefer a convex mirror as a rear-view mirror in vehicles because it gives a wider field of view, which allows the driver to see most of the traffic behind him. Convex mirrors always form a virtual, erect, and diminished image of the objects placed in front of it.