Question

an equiconvex lens ( of refractive index 1.5) is placed in contact with plane mirror as shown in figure. a small needle with its tip on the principle axis is moved along the axis until its inverted image is found at the position of the needle. the distance of the needle from the lens is measured to be 30cm. now a few drops of a liquid are put in between the lens and the plane mirror and the new position of the image is found to be located at 45cm. calculate the refractive index of the liquid.

Answer 1

I don't know frnd! Sorry!