Question

1) Inside a spacecraft flying past the moon at 0.99c (0.99*3.0*108 m/s) a pendulum is swinging. It takes 1.0 sec to swing from the spacecraft’s point of view.

a. How long does it take from the moon bases’ perspective?

b. A pendulum on the moon takes 10.0 sec. to swing from the moon’s perspective. How long does it takes from the spacecraft’s perspective?

2) A laser used to destroy cancer emits light at a wavelength of 600nm in pulses 10ms long. The average power per pulse expended is 1.000 watts.

a. How much energy is in each pulse in joules?

b. What is the energy of one photon in electron volts?

c. How many photons are in each pulse?

Answer 1

#Hi, if you are happy and find this useful please thumbs up. In case, if you have any query regarding the solution please let me know in the comments section below. We can discuss. Thanks!!