A convex lens of refractive index 3 2 has a power 2.5. If it is placed in a liquid of refractive index 2 , the new power of the lens is

Step-by-step solution

Using Lens maker's formula, 1 f = P =( -1) ( 1 R ₁ - 1 R ₂ ) When placed in liquid the power is given by P^ = ( ^ -1 ) ( 1 R₁ - 1 R₂ ) Where refractive index of lens in the liquid, aligned & ^ = _l = 3 / 2 2 = 3 4 & P^ P = ^ -1 -1 = 3 4 -1 3 2 -1 = - 1 4 1 2 =- 1 2 & P^ =- 1 2 P=- 1 2 2.5=-1.25 D aligned