A rig's current is turned up. Nothing else changes. What happens to the force on the wire?
One more rig: the same magnets, the same current. This time the length of wire inside the field changes. Wide magnet poles leave a long stretch of wire crossing the field; narrow poles leave a short stretch.
With a short stretch of wire crossing the field, the force is small.
Wider poles go in, so a longer stretch of the same wire crosses the field. The current is unchanged. The force is bigger.
Extra wire is coiled up well outside the field. The force does not change.
Wire outside the field adds nothing. Only the length inside the field feels the field's push.
Wider poles put a longer stretch of the wire into the field. Nothing else changes. What happens to the force?
Extra wire is added outside the field. Nothing else changes. What happens to the force?
A rig is rebuilt so twice as much wire sits between the poles, with the same current and the same magnets. What happens to the force?
Only the length of wire inside the field has changed.
A longer length inside the field means a bigger motor-effect force.
The force gets bigger.
A long lead joins a rig to a distant battery. The lead runs far from the field. Does the lead's length change the force?
The lead lies outside the field.
Wire outside the field adds nothing to the force.
No. The lead's length does not change the force.
A student says wire outside the field adds nothing to the force. Is the student correct?
Two rigs carry equal currents between identical magnets. Rig J has 5 cm of wire in the field; rig K has 10 cm. Which wire feels the bigger force?
Which length decides the size of the motor-effect force on a wire?
A rig's force must get bigger, but the current must stay the same. Which change works?