Light with the wavelength of peak intensity from a star can just barely produce photoelectrons from manganese (φ = 4.1 eV). What is the temperature of the star?
A) 960 K
B) 23000 K
C) 9600 K
D) 96000 K
E) 2300 K

Question

Quizplus · Accepted Answer

We can use the formula for finding the wavelength of peak intensity: $\lambda_{max} = \frac{2.898 	imes 10^{-3} mK}{T}$.

To find the energy of a photon with this wavelength, we can use the formula $E = hc/\lambda$, where $h$ is Planck's constant and $c$ is the speed of light.

Setting the energy equal to the work function, we get $4.1 = hc/\lambda_{max}$.

Combining these two equations and solving for $T$, we get $T = \frac{2.898 	imes 10^{-3} mK}{4.1 hc}$. Plugging in the values for $h$ and $c$, we get $T = 9600$ K.

Light with the Wavelength of Peak Intensity from a Star