Chapter 4
Astronomy Today · 6 exercises
Problem 1
What is the energy (in electron volts-see More Precisely 4-1) of a 450 -nm blue photon? A 200 -nm ultraviolet photon?
6 step solution
Problem 2
What is the energy (in electron volts) of a \(100-\mathrm{GHz}\) \(\left(1 \text { gigahertz }=10^{9} \mathrm{Hz}\right)\) microwave photon?
5 step solution
Problem 3
What are the wavelengths of (a) a 2 -eV red photon, (b) an \(0.1-\mathrm{eV}\) infrared photon, and \((\mathrm{c})\) a 5000 -eV ( 5 -keV ) X-ray?
4 step solution
Problem 4
How many times more energy has a 1 -nm gamma ray than a 10 -MHz radio photon?
5 step solution
Problem 5
List all the spectral lines of hydrogen that lie in the visible range (taken to run from 400 to 700 nm in wavelength).
5 step solution
Problem 8
In a demonstration of the photoelectric effect, suppose that a minimum energy of \(5 \times 10^{-19} \mathrm{J}(3.1 \mathrm{eV})\) is required to dislodge an electron from a metal surface. What is the minimum frequency (and longest wavelength) of radiation for which the detector registers a response?
5 step solution