Find the height of image in the following diagram.

Options

A. 2 mm
B. 4 mm
C. 6 mm
D. 8 mm

Answer

B

Explanation

` (n _ 2 ) /( v ) = ( n _ 1 ) /( u ) = ( n _ 2 - n _ 1 ) /( R ) rArr ( 1- 2 ) /( v - 30 ) = ( 1 - 2 )/( - 20) `
` v = - 60 cm `
` m = ( h _ 2 ) /( h _ 1 ) = ( n _ 1 v ) / ( n _ 2 u ) = (2 ( - 60))/( 1 ( - 30)) = 4 `mm