A battery with a constant internal resistance is connected to a resistor of resistance 
, as shown.
The current in the resistor is 
for a time of 
. During this time 
of energy is dissipated by the internal resistance. What is the energy supplied to the external resistor during the and the electromotive force (e.m.f.) of the battery?
and the electromotive force (e.m.f.) of the battery is 
. (Option D)
