Question

A distant quasar is observed to have a redshift v/c = 0.15, where v is the
recession velocity of the quasar, and c = 300, 000 km/s is the speed of light.
(a) What is the recession velocity v of the quasar in units of km/s? (2 points)

A. 7.47 × 10−5 km/s
B. 45,000 km/s
C. 0.059 km/s
D. 1.43 km/s
E. 1.97 × 106 km/s

Answer 1

Answer on Question: 54933

A distant quasar is observed to have a redshift $v/c = 0.15$, where $v$ is the recession velocity of the quasar, and $c = 300$, $000 \, \text{km/s}$ is the speed of light.

(a) What is the recession velocity $v$ of the quasar in units of $\text{km/s}$? (2 points)

A. $7.47 \times 10^{-5} \, \text{km/s}$

B. $45,000 \, \text{km/s}$

C. $0.059 \, \text{km/s}$

D. $1.43 \, \text{km/s}$

E. $1.97 \times 106 \, \text{km/s}$

Solution:

$$v/c = 0.15$$ $$v = 0.15c = 0.15 \times 3 \times 10^5 \, \text{km/s} = 45,000 \, \text{km/s}$$

Answer: 45,000 km/s (B)