Question

Two convex lenses of each have power of +5Dand +2D.if they put in contact the resutant power of combination is.what

Answer 1

Given ,

➡The two lenses are in contact and both have +5 D and + 2 D power

We know that ,

The ability of lens to converge or diverge the light rays falling on it is called power of lens

$\large \mathtt{\fbox{P = \frac{1}{f \:(in \: m) } }}$

For n lens in contact , the equivalent power of lens (P) is given by

$\large \mathtt{\fbox{P = P_{1} +P_{2} \: .. \: +P_{n} }}$

Thus ,

P = 5 + 2

P = 7 D

Hence , the equivalent power of lens is 7 D