Question

OB' value in the above diagram​

Answer 1

$\frac{1}{f} = (\frac{nl}{nm} - 1)( \frac{1}{r1} - \frac{1}{r2} )$

nl/nm=3/2(1)-1=1/2

r1=-36cm

r2=36cm

$\frac{1}{f} = ( \frac{1}{2} )( \frac{ - 2}{36} )\\ f = - 36cm$

u=-60cm

$\frac{1}{f} = \frac{1}{v} - \frac{1}{u} \\ \frac{1}{ - 36} - \frac{1}{60} = \frac{1}{v} \\ \frac{1}{v} = \frac{96}{ -2160 } \\ v = - 22.5cm$

i hope this helps ( ╹▽╹ )