Which Type of Photon Has the Most Mass?

[TheTourist]

Which of the following has the greatest mass?
An infrared photon
A UV photon
An optical photon
An x-ray photon
This question is on a past exam paper that I'm going through. I thought photons have no rest rest mass, so how can one have more mass than another? I have tried the textbook, the lecture notes and the internet but can't find anything of any use.

 

[DaveC426913]

Trick question?

 

[TheTourist]

I thought that, but it seems a bit harsh to put it on a proper exam, when it gives you no option but to answer one ; it's the multiple choice part of the exam.

 

[Doc Al]

They are most likely talking about the so-called 'relativistic mass', not the usual rest mass. They should have just asked which photon has the greatest energy.

Read: http://www2.corepower.com:8080/~relfaq/photon_mass.html"

 

[DaveC426913]

...it gives you no option but to answer one ; it's the multiple choice part of the exam.

Ah. Then that would be a nasty trick...

 

[TheTourist]

ah thanks very much, I didn't think of that.