# A Symmetric Double Convex Lens in Cut in Two Equal Parts by a Plane Perpendicular to the Principal Axis. If the Power of the Original Lens Was 4 D, the Power a Cut-lens Will Be - Science

MCQ

A symmetric double convex lens in cut in two equal parts by a plane perpendicular to the principal axis. If the power of the original lens was 4 D, the power a cut-lens will be

• 2 D

• 3 D

• 4 D

• 5 D.

#### Solution

2 D

The lens is cut into two equal parts by a plane perpendicular to the principal axis. Thus, the radius of curvature of both the lenses become half of its original value.
As,
$f = \frac{R}{2}$
$P = \frac{1}{f}$
Radius of curvature becomes half. Therefore, the focal also
reduces to half its original value.
Thus, the power (P) of the two cut-lenses will be equal.
P = 4 D
P = 2 D

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#### APPEARS IN

HC Verma Class 11, 12 Concepts of Physics 1
Chapter 18 Geometrical Optics
MCQ | Q 12 | Page 411
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