Light Travel and Measurement Concepts

What does a light-year represent?

• The time it takes for light to travel around the Earth.

• The distance light travels in one year.

• The speed of light in a vacuum.

• The age of a star.

Approximately how many kilometers does light travel in one year?

• 300,000 km

• 150 million km

• 9.5 trillion km

• 4.24 billion km

If you could travel at the speed of light, how many times could you circle the Earth in one second?

• Once

• Almost 8 times

• 15 times

• 300,000 times

How long does it take for light from the Sun to reach Earth?

• 1 second

• 8.3 minutes

• 4.24 years

• 1 year

What is the primary reason astronomers use light-years to measure distances in space?

• Light-years are easier to calculate than kilometers.

• Light-years account for the varying speed of light.

• The distances in space are so vast that using kilometers results in unwieldy numbers.

• Light-years are a more precise unit of measurement.

Speed of light is .................km/sec

• 9X 10 ^6

• 3X10^6

• 5X10^6

• none of these