A travelling microscope reads 10.08 cm for a spot on the table, 12.48 cm for its apparent position through a glass slab, and 14.88 cm for the slab top. Least count is 0.01 cm. Find the percentage error in the refractive index.

Question

G1 Physics · Accepted Answer

Real thickness =14.88−10.08=4.80 cm and apparent thickness =14.88−12.48=2.40 cm, so μ=2. For each difference the absolute error is 0.02 cm. Hence Δμ/μ =0.02/4.80 +0.02/2.40 =0.0125. Percentage error =1.25%.