Question

The period of rotation of the sun at its equator is T and its radius is R. Then the Doppler wavelength shift expected for light with wavelength l emitted from the edge of the sun's disc is – [c = speed of light]

• A. ± $\frac{R\lambda}{cT}$
• B. ± $\frac{T\lambda}{2\pi Rc}$
• C. ± $\frac{2\pi Rc}{T\lambda}$
• D. ± $\frac{2\pi R\lambda}{cT}$

Answer 1

Answer: (D)

± $\frac{2\pi R\lambda}{cT}$

Answer 2

Dl = ± $\frac { \mathrm { v } } { \mathrm { c } }$ l

v = Rw = $\frac { \mathrm { R } 2 \pi } { \mathrm {~T} }$

Dl = ± $\frac { 2 \pi \mathrm { R } \lambda } { \mathrm { cT } }$