A ray goes from medium A to B. Its speed changes from 2.4 × 10⁸ m/s to 1.8 × 10⁸ m/s. If its wavelength in A is 640 nm, what is its wavelength in B?
Options

Question

A ray goes from medium A to B. Its speed changes from 2.4 × 10⁸ m/s to 1.8 × 10⁸ m/s. If its wavelength in A is 640 nm, what is its wavelength in B?

G1 Physics · Accepted Answer

Since frequency is unchanged, λB/λA=vB/vA=1.8/2.4=3/4. Thus λB=480 nm.