Question

The speed of light in a vacuum is 2.998 x 108 m/s. What is its speed in (a) km/h; (b) mi/min?

Answer 1

Answer :

(a) The speed of light in km/hr is, $10.7928\times 10^8Km/hr$

(b) The speed of light in mi/min is, $1.117\times 10^7mi/min$

Explanation :

(a) We are given the speed of light is, $2.998\times 10^8m/s$

As we know that,

$1m=\frac{1}{1000}m$

and,

$1s=\frac{1}{3600}hr$

By using both the conversion, we get:

$2.998\times 10^8m/s$

$\Rightarrow \frac{2.998\times 10^8m}{1s}\times \frac{3600s}{1hr}\times \frac{1km}{1000m}$

$\Rightarrow 10.7928\times 10^8Km/hr$

The speed of light in km/hr is, $10.7928\times 10^8Km/hr$

(b) We are given the speed of light is, $2.998\times 10^8m/s$

As we know that,

$1m=\frac{1}{1609.34}mi$

and,

$1s=\frac{1}{60}min$

By using both the conversion, we get:

$2.998\times 10^8m/s$

$\Rightarrow \frac{2.998\times 10^8m}{1s}\times \frac{60s}{1min}\times \frac{1mi}{1609.34m}$

$\Rightarrow 1.117\times 10^7mi/min$

The speed of light in mi/min is, $1.117\times 10^7mi/min$