When a surface is irradiated with light of wavelength 4950A˚ , a photocurrent appears which vanishes if a retarding potential greater than 0.6 volt is applied across the phototube. When a second source of light is used, it is found that the critical retarding potential is changed to 1.1 volt.
If the photoelectrons (after emission from the source) are subjected to a magnetic field of 10 tesla, the two retarding potentials would
a. uniformly increase
b. uniformly decrease
c. remain the same
d. None of these