Physics

Physics

Problem

A laser beam in air (index of refraction nair=1.00n_{\text{air}}=1.00) strikes the surface of a rectangular slab of an optically transparent solid. The beam makes an angle of 35.0∘35.0^{\circ} with the normal to the surface; inside the slab the beam is observed to propagate at an angle of 22.0∘22.0^{\circ} to the same normal. A manufacturer’s handbook lists the following candidate materials and their accepted indices of refraction at the laser’s wavelength: • Crown glass 1.52 • Flint glass 1.62 • Fused quartz 1.46 • Lucite 1.49 (a) Calculate the index of refraction of the unknown solid. (b) Determine the speed of light in the solid, expressing your answer in m s−1\text{m}\,\text{s}^{-1} to three significant figures. (c) Using your result from part (b), identify which material from the manufacturer’s list best matches the slab. Justify your choice quantitatively.

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