An FM radio transmitter broadcasts at a frequency of MHz
PHYSICS · Multi-part · Fermi University Physics · Quantum Mechanics · Origins of quantum theory · Origins of quantum theory
Quantum Mechanics: From the Photon to the Hydrogen Atom, Ch Light in lumps: blackbody radiation, the photoelectric effect and Compton scattering
Problem
An FM radio transmitter broadcasts at a frequency of 100 MHz. Photons of this radiation fall on a zinc surface of work function W=4.3 eV. Treat the transmitter as working at ordinary broadcast powers and ignore any heating of the zinc. Take c=3.00×108ms−1, h=6.626×10−34 J s and hc=1240 eV nm.
((a)) Find the wavelength of this radiation, in metres.
((b)) Find the energy of one photon, in electronvolts.
((c)) Find the momentum of one such photon, in kg m s−1.
((d)) Using your answer to part (b), explain why making the transmitter brighter does not let one photon free one electron from the zinc.