(a)
For the correct answer:
Circles drawn.
Concentric (by eye) with wire.
Arrow drawn clockwise on/near field (line).
Whenever an electric current flows through a straight conductor, it generates a magnetic field in the shape of concentric circles radiating outward. To determine the exact direction of these circular field lines, you use the right-hand grip rule: pointing your thumb in the direction of the current (downwards into the card) causes your fingers to curl in a clockwise direction. Thus, you must draw circles around the wire with clear clockwise arrows.
(b)(i)
For the correct answer (any two):
Increase current (in wire)
Increase strength of magnets or magnetic field
The magnetic force acting on a current-carrying wire placed in an external magnetic field (often called the motor effect) is directly proportional to both the current and the magnetic field strength. Therefore, ramping up the electrical current or using significantly stronger permanent magnets will correspondingly increase the physical upward push experienced by the wire.
(b)(ii)
For the correct answer:
Reverse the (direction of the) current (in the wire).
Reverse the magnetic field (or move poles closer together, though reversing is the standard method).
Fleming’s Left-Hand Rule dictates the directional relationship between current, magnetic field, and the resulting force. Because these three vectors are perfectly perpendicular, flipping the direction of exactly one of the inputs (either making the current flow from Y to X, or physically swapping the North and South magnet poles) will precisely invert the direction of the resulting force, making it push downwards instead of upwards.
