NCERT Solutions for Class 10 Science Chapter 10
Important Board Questions
Light – Reflection and Refraction
NCERT Books for Session 2022-2023
CBSE Board and UP Board
Answer in one word/one sentence.
Questions No: 12 part: iv
Define the principal focus of a concave mirror.
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The point at whichrays parallel to principal axiscoming from infinity convergeafter being reflected from concave mirroris called the principal focus of concave mirror.
Principal focus of a concave mirror is the point on its principal axis, where light rays coming parallel to the principal axis actually converge after reflection from the mirror.
The principal focus of a concave mirror is the point where parallel rays of light that are initially traveling towards the mirror either converge (for a concave mirror) or appear to diverge from (if extended backward). This point is a key focal point for the mirror and is denoted by the symbol “F.”
In a concave mirror, which is curved inward, the principal focus is a real focal point. It is the point where rays parallel to the mirror’s principal axis converge after reflecting off the mirror. This property makes concave mirrors useful in applications such as focusing light in optical systems, including telescopes and certain types of cameras. The distance from the mirror’s surface to the principal focus is known as the focal length. The focal length is a crucial parameter that determines how strongly the mirror converges or diverges light.
The principal focus of a concave mirror is an essential concept in optics and plays a significant role in understanding image formation and magnification in mirrors.