Q.
Under what conditions current passing through the resistance R can be increased by short circuiting the battery of emf E2 ? The internal resistances of the two batteries are r1 and r2 respectively.
The current through the circuit before the battery of emf E2 is short circuited, is i1=r1+r2+RE1+E2...(i)
After short circuiting the battery of emf E2, current through the resistance R would be i2=R+I1E1...(ii)
Since, from Eqs. (i) and (ii), we get i2>i1 ∴R+I1E1>R+I1+I2E1+E2
This gives E1I2>E2(R+r1)