Question

A concave lens has a focal length of 25cm. it's power in diaptor is​

Answer 1

As we know that :

`\begin{gathered}\large{\boxed{\sf{P \: = \: (1)/(f)}}} \\ \\ \rightarrow {\sf{P \: = \: (1)/(-25)}}\end{gathered}`

Power, is in Meter. So divide focal length by 100

`\begin{gathered}\rightarrow {\sf{P \: = \: (1)/((-25)/(100))}} \\ \\ \rightarrow {\sf{P \: = \: (-100)/(25)}} \\ \\ \rightarrow {\sf{P \: = \:- 4}} \\ \\ \underline{\sf{\therefore \: Power \: of \: Concave \: lens \: is \: - \: 4D}}\end{gathered}`