Indicate which of the following sources produces the lowest energy photons.
a. A radio station with ν= 106.7 MHz
b. A dentist’s x-ray source with λ= 100 pm
c. The laser in a CD player with λ= 650 nm
d. A microwave oven with ν= 6.0×10¹⁰ Hz
e. Your cell phone with ν= 1.750 GHz
