An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is:
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Question

An air bubble in a glass slab with refractive index 1.5 (near normal incidence) is 5 cm deep when viewed from one surface and 3 cm deep when viewed from the opposite face. The thickness (in cm) of the slab is:

Options

G1 Physics · Accepted Answer

Step 1: Apparent depth = real depth/μ for normal viewing from air. Step 2: Actual distances of bubble from faces are 1.5 × 5 = 7.5 cm and 1.5 × 3 = 4.5 cm. Step 3: Slab thickness = 7.5 + 4.5 = 12 cm. Final answer: (C) 12 cm.