Question

Each of the batteries shown in figure has an emf equal to 5 V. Show that the magnetic field B at the point P  is zero for any set of values of the resistances. 

Answer 1

By appluing Kirchoff voltagee law,we can see that the current in the circuit is zero.
Net current in the circuit = 0
As
magnetic field is always proportional to the current flowing in the circuit hence,
Net magnetic field at point P = 0
Field at point P is independent of the values of the resistances in the circuit.