The wavelength of light of a particular wavelength received from a galaxy is measured on earth and is found to be 5 % more that its wavelength. It follows that the galaxy is:

Question

The wavelength of light of a particular wavelength received from a galaxy is measured on earth and is found to be 5 % more that its wavelength. It follows that the galaxy is: (A) Approaching the earth with a speed 3 × 107 ms -1 (B) Going away from the earth with a speed 1.5 × 10-7 ms -1 (C) Approaching the earth with a speed 1.5 × 107 ms -1 (D) Going away from the earth with a speed 1.5 × 107 ms -1

Tardigrade Admin · Accepted Answer

As wavelength is more that means galaxy is receding away from earth at speed given as v=(Δ λ/λ) × C=0.05 × 3 × 108 =1.5 × 107 m / s .

Q. The wavelength of light of a particular wavelength received from a galaxy is measured on earth and is found to be $5%$ more that its wavelength. It follows that the galaxy is:

Approaching the earth with a speed $3 \times 1 0^{7} m s^{- 1}$

Going away from the earth with a speed $1.5 \times 1 0^{- 7} m s^{- 1}$

Approaching the earth with a speed $1.5 \times 1 0^{7} m s^{- 1}$

Going away from the earth with a speed $1.5 \times 1 0^{7} m s^{- 1}$

As wavelength is more that means galaxy is receding away from earth at speed given as
$v = \frac{Δ λ}{λ} \times C = 0.05 \times 3 \times 1 0^{8}$
$= 1.5 \times 1 0^{7} m / s .$

Q. The wavelength of light of a particular wavelength received from a galaxy is measured on earth and is found to be 5% more that its wavelength. It follows that the galaxy is:

Approaching the earth with a speed 3×107ms−1

Going away from the earth with a speed 1.5×10−7ms−1

Approaching the earth with a speed 1.5×107ms−1

Going away from the earth with a speed 1.5×107ms−1