Temperature variation of different parts of a person's body can be detected by analyzing the emission pattern of which type of electromagnetic radiation?
a. microwave
c. x-rays
b. infrared
d. ultraviolet
Question 2
While standing at a crosswalk, you hear a frequency of 540 Hz from an approaching police car. After the police car passes, its frequency is 480 Hz. What is the speed of the police car? (speed of sound = 340 m/s)
a. 13.1 m/s
c. 20.0 m/s
b. 17.4 m/s
d. 26.2 m/s