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Power Of Lens And Mirror - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • Power of lens and mirror is considered one of the most asked concept.

  • 19 Questions around this concept.

Solve by difficulty

Direction:  In the following question, a statement of Assertion (A)  is followed by a statement of reason (R). Mark the correct choice as: 

Assertion: The power of a convex lens is positive and that of a concave lens is negative.

Reason: The power of lens is P =1f

 

A biconcave lens of power P vertically splits into two identical plano concave parts. The power of each part will be

A biconvex lens of focal length f is cut into two identical plano convex lenses. The focal length of each part will be

Concepts Covered - 1

Power of lens and mirror

Power and lens and mirror-

Power of a lens is defined as the reciprocal of focal length and Power of a mirror is defined as the negative of reciprocal of focal length.

                                                        So, 

                                                         

So,

PLens =1f and PMirror =1f


Where, f= focal length
The unit of power is Diopter, 1D=1m1
The sign of the focal length will be taken according to the sign convention which we have discussed in the previous concept.

The power of a combination of lenses in contact is the algebraic sum of the powers of individual lenses, so it can be written as -

PTotal =PI+P2+P3++Pn
 

Study it with Videos

Power of lens and mirror

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