The process of apparent change in frequency (or wavelength) of the light due to relative motion between the source of light and the observer is called Doppler's effect.

If V = actual frequency, V' = Apparent frequency, v = speed of source w.r.t stationary observer, c = speed of light

1. Source of light moves towards the stationary observer: When a light source is receding from an observer with a relative velocity v then the apparent frequency (v) is less than the actual frequency (v) of light. Thus apparent wavelength (λ') is greater the actual wavelength (λ).

For v < < c :

(i) Apparent frequency      v' = v(1+v/c) and

(ii) Apparent wavelength  λ' = λ(1+v/c)

(iii) Doppler's shift: Apparent wavelength < actual wavelength. This is called violet shift.

Doppler's shift  Δλ = λ.v/c

(iv) The fraction decrease in wavelength = Δλ/λ =v/c

2. Source of light moves away from the stationary observer : In this case v′<v and λ′>λ

For v < < c :

(i) Apparent frequency v' = v(1-v/c) and    (ii) Apparent wavelength λ' = λ(1+v/c)

(iii) Doppler's shift : Apparent wavelength > actual wavelength. This is called red shift.

Doppler's shift Δλ = λ.v/c

(iv) The fractional increase in wavelength = Δλ/λ =v/c

3. Doppler broadening: For a gas in a discharge tube, atoms are moving randomly in all directions. When spectrum of light emitted from these atoms is analyzed, then due to Doppler effect (because some atoms are moving towards detector, some atoms are moving away from detector), the frequency of a spectral line is not observed as having one value, but is spread over a range

                           ±Δv = ±(v/c)v , ±Δλ = ±(v/c)λ

This broadens the spectral line by an amount ( 2Δλ ). It is known as Doppler broadening. It is relaying on v, which in part is proportional to√T , where T is the temperature in Kelvin.

Email based Physics assignment help - homework help at Expertsmind

Are you searching physics expert for help with Doppler's effect of light questions?  Doppler's effect of light topic is not easier to learn without external help?  We at www.expertsmind.com offer finest service of Physics assignment help and physics homework help. Live tutors are available for 24x7 hours helping students in their Doppler's effect of light related problems. We provide step by step Doppler's effect of light question's answers with 100% plagiarism free content. We prepare quality content and notes for Doppler's effect of light topic under physics theory and study material. These are avail for subscribed users and they can get advantages anytime.

Why Expertsmind for assignment help

1. Higher degree holder and experienced experts network
2. Punctuality and responsibility of work
3. Quality solution with 100% plagiarism free answers
4. Time on Delivery
5. Privacy of information and details
6. Excellence in solving physics queries in excels and word format.
7. Best tutoring assistance 24x7 hours