Question

A symmetrical double convex lens is cut in two equal parts vertically, If the length of the original lens was $4$ cm.

then what will be the focal length of the cut lens ?

• A. 5
• B. 9
• C. 6
• D. 8

Answer 1

The correct option is D 8

If a symmetrical double convex lens is cut into two equal parts vertically,

then the focal length of cut lens is doubled.

Since ,focal length of original double convex lens $=4$ cm.

Then,

Focal length of cut lens $=4\times 2=8$ cm.