Question

5. It takes time 8 min for light to reach from the sun to the earth surface. If speed of light is taken to be 3 x 10^8 m/s, find the distance from the sun to the earth in km.​

Answer 1

Answer:-

Distance from the Sun to the Earth is 1.44 × 10⁸ km .

Explanation:-

We have :-

→ Time taken = 8 min

→ Speed of light = 3 × 10⁸ m/s

________________________________

Firstly, let's convert the given unit of time from 'min' to 'sec' .

⇒ 1 min = 60 sec

⇒ 8 min = 60(8)

⇒ 480 sec

________________________________

We know that :-

Distance = Speed × Time

⇒ Distance = 3 × 10⁸ × 480

⇒ Distance = 1440 × 10⁸

⇒ Distance = 1.44 × 10¹¹ m

Finally let's convert the unit of distance from 'm' to 'km' .

⇒ 1 m = 10⁻³ km

⇒ 1.44 × 10¹¹ m = 1.44 × 10¹¹ × 10⁻³

⇒ 1.44 × 10⁸ km

Answer 2

Answer:

Given :-

• It takes time 8 mins for reach from the sun to the Earth surface.
• Speed of light is taken to be 3 × 10⁸.

To Find :-

• What is the distance from the sun to the Earth in km.

Formula Used :-

$\clubsuit$ Distance Formula :

$\longmapsto \sf\boxed{\bold{\pink{Distance =\: Speed \times Time}}}$

Solution :-

First, we have to convert minutes into seconds :

Given :

• Time = 8 minutes

$\implies \sf Time =\: 8\: minutes$

Then,

$\implies \sf Time =\: 8 \times 60\: seconds$

$\implies\sf\bold{\green{Time =\: 480\: seconds}}$

Now, we have to find the distance between the sun to earth in km :

Given :

• Speed = 3 × 10⁸ m/s
• Time = 480 seconds

According to the question by using the formula we get,

$\implies \sf Distance =\: 3 \times 10^8 \times 480$

$\implies \sf Distance =\: 3 \times 480 \times 10^8$

$\implies \sf Distance =\: 1.44 \times 10^{11}\: m$

As we know that, [ 1 m = 10-³ km ]

So,

$\implies \sf Distance =\: 1.44 \times {{10}^{11}} \times {{10}^{- 3}}$

$\implies \sf Distance =\: 1.44 \times {10}^{(11 - 3)}$

$\implies \sf Distance =\: 1.44 \times {10}^{(8)}$

$\implies\sf\bold{\red{Distance =\: 1.44 \times {10}^{8}\: km}}$

$\therefore$ The distance between the sun to the Earth in km is 1.44 × 10⁸ km .

$\rule{150}{2}$

$\bigstar$ EXTRA INFORMATION :

$\clubsuit$ Time Formula :

$\longmapsto \sf\boxed{\bold{\pink{Time =\: \dfrac{Distance}{Speed}}}}$

$\clubsuit$ Speed Formula :

$\longmapsto \sf\boxed{\bold{\pink{Speed =\: \dfrac{Distance}{Time}}}}$