Light of wavelength 589 nm in vacuum passes through a piece of fused quartz of index of refraction n
Light of wavelength 589 nm in vacuum passes through a piece of fused quartz of index of refraction n = 1.458. What is the frequency of the light in fused quartz? [Speed of light c = 3.00 x 108 ms-1]
Light of wavelength 589 nm in vacuum passes through a piece of fused quartz of index of refraction n = 1.458. What is the frequency of the light in fused quartz? [Speed of light c = 3.00 x 108 ms-1]
When light enters a new material, its speed and wavelength change, but its frequency does not. The frequency in quartz equals the frequency in vacuum.
f = c/λ = (3.00 × 10⁸)/(589 × 10⁻⁹) ≈ 5.09 × 10¹⁴ Hz.
The 1.77 × 10¹⁴ Hz option comes from wrongly dividing by n = 1.458 as well; that would be wrong because n changes the speed and wavelength, not the frequency.
Was this explanation helpful?
Something wrong or missing? Tell us — we read every report and fix issues fast.