Question

A lens is made of flint glass (refractive index= 1.5) . when the lens is immersed in liquid of refractive index 1.25, the focal length is

Answer 1

Dear students, here is your answer.

If a glass lens is immersed in a liquid, then the equation for the focal length will be,

1f=(n glass / n liquid−1){1R1−1R2}

⇒1f=(32/54/−1){1R1−1R2}



⇒1f=(6−55){1R1−1R2}


⇒1f=15{1R1−1R2}