Given,
For convergent lens,
μa=1, refractive index of air
μg=1.5, refractive index of glass
PC=+5D
the Power of the lens is given by the lens maker formula
PC=1f=(μgμa−1)(1R1−1R2)=+5D. . . . . .(1)
Now, When convergent lens immersed in a liquid of refractive index μ, convergent lens act as a diverging lens of focal length −100cm
By lens maker formula,
Pd=1f=(μgμ−1)(1R1−1R2)=−100100=−1D. . . . . . (2)
Divide equation (1) by equation (2), we get
PCPd=(μgμa−1)μgμ−1=−5
μgμ1=−5(μgμ−1)
1.51−1=−5(1.5μ−1)
0.55=−(1.5μ−1)
μ=53