In the process of ab rod moving from rest to right, the kinetic energy of ab rod gradually increases, and Joule heat is generated in the circuit. According to the functional relationship, the work done by external force should be equal to the sum of the internal energy generated by the whole loop and the kinetic energy obtained by the rod.

Therefore, the work done by the external force F is greater than the electric work consumed by the whole circuit.

The power of the magnetic field acting on the ab rod is equal to the electric power consumed by the whole circuit. Because ab rod also has a resistor, the magnetic field power acting on ab rod is greater than the electric power consumed by resistor R. 。

So the answer is: greater than, greater than.