Author Question: During a thunderstorm, an observer notes that 10 s elapsed between the lightning flash and the sound ... (Read 72 times)

mckennatimberlake · **on:** Jul 28, 2018

During a thunderstorm, an observer notes that 10 s elapsed between the lightning flash and the sound of the thunder. What is the approximate distance, in miles, from the observer to the lightning?

Question 2

A helium-neon laser emits red light having a wavelength of 6.4 107 m and a power of 0.5 mW. How many photons are emitted each second?
a. 6.4 1038
b. 1.6 1021
c. 3.2 1025
d. 2.6 1018
e. 1.6 1015