The spectrum of sodium includes two lines at wavelength $588.995 \mathrm{nm}$ and $589.592\mathrm{nm}$. A sodium lamp is viewed by a diffraction grating that just manages to resolve these two lines in the third-order at $12°$. Determine

a. The slit spacing $d$ of the grating.

The spectrum of sodium includes two lines at wavelength $588.995 \mathrm{nm}$ and $589.592\mathrm{nm}$. A sodium lamp is viewed by a diffraction grating that just manages to resolve these two lines in the third order at $12°$. Determine

b. The total number of ruling on the grating.

Explain, with the help of diagrams, the Doppler's effect. Shows clearly the cases of source that 

a. Moves towards and 

b. Goes away from a stationary observer.

A source approaches a stationary observer at  $40\mathrm{m}/\mathrm{s}$ emitting sound of frequency $500\mathrm{Hz}$. 

a. Determine the frequency the observer measure.

A source approaches a stationary observer at  $40\mathrm{m}/\mathrm{s}$ emitting sound of frequency $500\mathrm{Hz}$. 

b. Calculate the wavelength of the sound as measured by i the source and ii the observer.

A source is moving away from a stationary observer at  $32\mathrm{m}/\mathrm{s}$ emitting sound of frequency $480\mathrm{Hz}$. 

a. Determine the frequency the observer measure.

A source is moving away from a stationary observer at $32\mathrm{m}/\mathrm{s}$ emitting sound of frequency $480\mathrm{Hz}$. 

b. Calculate the wavelength of the sound as measured by i the source and ii the observer.