Author Question: In order to keep its food hot, a restaurant will place it under which type of lamp? a. ultraviolet ... (Read 72 times)

vHAUNG6011 · **on:** Jul 28, 2018

In order to keep its food hot, a restaurant will place it under which type of lamp?
a. ultraviolet
c. infrared
b. visible light
d. X-ray

Question 2

A train station bell gives off a fundamental tone of 1000 Hz as the train approaches the station at a speed of 20.0 m/s. If the speed of sound in air is 335 m/s, what will be the apparent frequency of the bell to an observer riding the train?
a. 1060 Hz
c. 943 Hz
b. 1070 Hz
d. 940 Hz