A rocket is receding from earth with a velocity 0.2c . It emits a signal of frequency 4× 107Hz . The frequency as observed on earth will be:

Question

A rocket is receding from earth with a velocity 0.2c . It emits a signal of frequency 4× 107Hz . The frequency as observed on earth will be: (A)  4× 106Hz  (B)  3.3× 107Hz  (C)  3× 106 Hz  (D)  5× 107Hz

Tardigrade Admin · Accepted Answer

Apparent frequency v=v( 1-( upsilon /c) ) =4× 107( 1-(0.2c/c) )=3.2× 107Hz

Q. A rocket is receding from earth with a velocity $0.2 c$ . It emits a signal of frequency $4 \times 10^{7} Hz$ . The frequency as observed on earth will be:

$4 \times 10^{6} Hz$

$3.3 \times 10^{7} Hz$

$3 \times 10^{6} Hz$

$5 \times 10^{7} Hz$

Apparent frequency $v = v (1 - \frac{υ}{c})$ $= 4 \times 10^{7} (1 - \frac{0.2 c}{c}) = 3.2 \times 10^{7} Hz$

Q. A rocket is receding from earth with a velocity 0.2c . It emits a signal of frequency 4×107Hz . The frequency as observed on earth will be:

4×106Hz

3.3×107Hz

3×106Hz

5×107Hz