a) Look at the photograph of the lab set-up. Since the light source gets very ho

Question

a) Look at the photograph of the lab set-up. Since the light source gets very hot, what affect do the heat photons have on photoemission?
1- none, since the infrared photons are absorbed by the air before they reach the metal
2- they increase the number of photoelectrons, but by the same amount no matter how hot the light source
3- none, since infrared photons are below the cut-off frequency
4- they increase the number of photoelectrons; the hotter the light source, the more effect they have
5-they decrease the number of photoelectrons by heating the metal and raising the work function

b) In procedure 1: when you increase the voltage V1 (the retarding potential), you expect the output voltage V2 to
1 - increase
2- remain the same
3- first increase, then decrease
4- first decrease, then increase
5- decrease

c) In procedure 3, you use the same set-up to measure the stopping potential Vs through different filters. Suppose a filter allowed through only light of frequency fo (the cut-off frequency) or lower. In this case, what would the stopping potential be?
1 - zero
2 - greater than zero: electrons escape, and must be stopped from drifting to the anode
3- you cannot tell, since different electrons will escape with different speeds
4- you need no stopping potential because no electrons escape from the metal

Procedure link here: 

http://www.physics.qc.edu/files.php?attach=254

Explanation / Answer

The number of emissions of electrons is only dependent on the frequency of the light and is defined as the WORK function. http://en.wikipedia.org/wiki/Work_function#Photoelectric_work_function

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.