Answer:
Light travels at 3x10^8 metres per second. A star is 4.2x10^17 metres away from Earth. Calculate the number of seconds it takes for light from this star to reach Earth. Give your answer in scientific notation.
Answer:
To calculate the number of seconds it takes for light from the star to reach Earth, we can use the formula:
Time = Distance / Speed
Given:
Speed of light = 3 × 10^8 meters per second
Distance from the star to Earth = 4.2 × 10^17 meters
Plugging in the values:
Time = (4.2 × 10^17 meters) / (3 × 10^8 meters per second)
To divide these values, we can subtract the exponents:
Time = 4.2 × 10^(17-8) seconds
Simplifying the exponent:
Time = 4.2 × 10^9 seconds
Therefore, it takes approximately 4.2 × 10^9 seconds for light from this star to reach Earth.
