The circuit illustrated contains a vertical wire, a resistor $R$ and a battery. The magnetic field close to the wire is also depicted. Two modifications are then made to the circuit: • The battery polarity is reversed. • The resistor $R$ is swapped for a different resistor with a smaller resistance than $R$. What effect will these modifications have on the magnetic field near the wire?
- Adirection of magnetic field: opposite; strength of magnetic field: same
- Bdirection of magnetic field: same; strength of magnetic field: weaker
- Cdirection of magnetic field: opposite; strength of magnetic field: stronger
- Ddirection of magnetic field: same; strength of magnetic field: stronger