Answer:
12 cm
Explanation:
We shall use Lens makers formula here which is as follows
[tex]\frac{1}{F} =(\mu-1) (\frac{1}{R_1} -\frac{1}{R_2})[/tex]
Put μ = 1.5 , R₁ = 10 cm ,R₂ = - 15 cm ( according to sign convention )
[tex]\frac{1}{F} =(1.5-1) (\frac{1}{10} -\frac{1}{-15})[/tex]
= .5 x ( 15 + 10 ) / 15 x 10
= [tex]\frac{25}{2\times10\times15}[/tex]
F = 12 cm