Home › UP Board Class 10 › Science › Light - Reflection and Refraction › The principal focus of a concave lens is:
The principal focus of a concave lens is:
AA virtual point from which parallel rays appear to diverge
BA real point where rays converge (option)
COn the same side as the object
DOn the optical centre
Answer & Solution
Correct answer: A. A virtual point from which parallel rays appear to diverge
1. A concave lens diverges parallel incident rays.
2. Tracing the diverging rays backwards, they appear to come from a virtual point in front of the lens.
3. This virtual point is the principal focus of the concave lens.
_Source: NCERT Class 10 Science, Ch 9 "Light Reflection and Refraction", §9.4.1_
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