BITSAT 2024 Shift 1 Paper

Power of an equiconvex lens is given as P diopters, which relates to its focal length f by the equation P=‌

1

f

.
When this equiconvex lens is divided into two symmetrical halves using a plane that includes the principal axis, each half retains the same focal length f. As a result, the power of each half-lens remains the same as the original lens, maintaining the relation:
P′=‌

1

f

‌‌⇒‌‌P′=P
Therefore, the ratio of the power of each half to the original lens power is:
‌

P′

P

=1
Thus, the ratio of the power of the two halves is 1:1.