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Question
Explain the following term related to spherical lenses: focal length
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Solution
Focal Length:-
The focal length of a lens is the distance between optical centre and principal focus of the lens.
RELATED QUESTIONS
Image formed by a convex ______ is always virtual and smaller in size.
We can obtain a real, enlarged and inverted image by a concave mirror.
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- angle of incidence?
- angle of reflection?
A student obtained on a screen the sharp image of a candle flame placed at the farther end of laboratory table using a concave mirror. For getting better value of focal length of the mirror, the teacher suggested to him to focus the sun. What should the student do?
(A) Should move the mirror away from the screen.
(B) Should move the mirror towards the screen.
(C) Should move the mirror and screen both towards the sun.
(D) Should move only the screen towards the sun.
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How will you distinguish between a plane mirror, a concave mirror and a convex mirror, without touching them?
The boxes in figure (a, b, c) represent mirrors; insert a mirror which will reflect the incident ray as shown in the diagram.
