Speed of Light Questions

PhysicsLight Unit

Numero 1

• The sun is about 150 million kilometers from earth. How long does it take light from the sun to reach earth? (The speed of light is 3x108 m/s.)

Question 2

• The horsehead nebula in Orion is 1500 light-years away; the Andromeda galaxy is 2 million light-years away; the most distant quasars are over 10 billion light-years away. Is it possible to know what these objects look like right now? Why or why not?

Nombre 3

• A light year is a unit of distance, the distance light travels in one year. How many kilometers long is a light-year?

Answers

• 1. t = 8.3 minutes• 2. No, it takes a long time for that

light to reach us.• 3. 1light-year = 9.5 x 1012 km