How long will it take light moving at 300,000 km/s to reach us from the sun? The sun is 15,000,000 km from earth.
Answers
It will take 8 minutes and 3 seconds for light to reach the earth.
GIVEN
Speed of light = 300,000 km/s
Distance from the sun to the earth = 15,000,000 km
TO FIND
Time taken by the light to reach the Earth
SOLUTION
We can simply solve the above problem as follows;
It is given,
Distance from the sun to the earth = 15,000,000 km
We can also write it as, 15 × 10⁶ km
Speed of light = 300,000 km/s
We can also write it as = 3 × 10⁵ km/s
Applying the formula,
Speed = Distance/Time
3 × 10⁵ = 15 × 10⁶/ time
Time = 15 × 10⁶/3 × 10⁵
Dividing 15 by 3 and bringing 10⁵ in the numerator by reversing the sign of the exponent.
= 5 × 10⁶ × 10⁻⁵
We know that,
aʷ × aᵉ = aʷ⁺ᵉ
Therefore,
Time = 5 × 10¹ = 500 sec
Converting the calculated time into minutes
Time = 500/60 = 8.3 seconds
Hence, It will take 8 minutes and 3 seconds for light to reach the earth.
#Spj2
The light takes 50 seconds to reach us from the sun.
The light takes 50 seconds to reach us from the sun. Given,
Distance between the sun and the earth=15000000 km
Speed of light=300000 km/s.
To find,
the time light takes to reach us from the sun.
Solution:
- Speed is equal to the ratio of distance covered and the time taken to cover that distance.
- Speed=Distance covered /Time taken.
- Its S.I. unit is m/s.
- 1 hour=60 minutes.
- 1 minute=60 seconds.
- 1 hour=60 x 60 seconds.
- 1 hour=3600 seconds.
- 1 second=1/3600 hour.
- 1 second=0.00028 hour
The speed of light in km/h will be,
=300000/0.00028 km/h
=1071428571 km/h.
The time taken to reach us,
Speed=Distance covered /Time taken
1071428571=15000000/Time taken
Time taken=15000000/1071428571
Time taken=0.014 hours.
0.014 hours into seconds,
=0.014x3600 seconds
=50.4 seconds
=50 seconds.
Thus, the light reaches us in 50 seconds.
#SPJ2