When the collector plate A is positive with respect to the
emitter plate C, the electrons are attracted to it The
emission of electrons causes flow of electric current in
the circuit The potential difference between the emitter
and collector plates is measured by a voltmeter (V)
whereas the resulting photo current flowing in the circuit
is measured by a microammeter (mA) The photoelectric
current can be increased or decreased by varying the
potential of collector plate A with respect to the emitter
plate C