A microscope M is focused on an object P . A glass slab having a thickness of 2.1 cm and a refractive index of 1.5 is inserted between P and M . Determine the distance by which the microscope must be shifted to bring the object back into focus.

Step-by-step solution

When a glass slab of thickness t and refractive index is inserted between an object and a microscope, the apparent shift of the object is given by: x = t (1 - 1 ) Given t = 2.1 cm and = 1.5 = 3 2 , substituting these values into the formula gives: x = 2.1 (1 - 2 3 ) x = 2.1 1 3 x = 0.7 cm The object appears to be shifted closer by 0.7 cm . Therefore, the microscope must be shifted by 0.7 cm to bring the object back into focus.