Practice identifying whether to use Fleming's left-hand rule for motors, Fleming's right-hand rule for generators, or another magnetic field rule in common electromagnetism situations.
Read each problem carefully. Decide which hand rule applies, then explain your reasoning using the ideas of force, motion, magnetic field, and current.
Choosing the correct rule for motor effect and generator effect problems
Physics - Grade 9-12
- 1
A current-carrying wire is placed between the north and south poles of a magnet. The wire experiences a force and begins to move. Which hand rule should you use to predict the direction of the force on the wire?
- 2
A coil is rotated inside a magnetic field, and an electric current is induced in the coil. Which hand rule should you use to find the direction of the induced current?
- 3
A student says, "I see current and a magnetic field, so I should always use the left-hand rule." Explain why this is not always correct.
- 4
In a simple electric motor, a battery sends current through a coil inside a magnetic field. The coil turns because forces act on its sides. Which hand rule applies, and why?
- 5
In a bicycle dynamo, a magnet rotates near a coil and produces an electric current for the light. Which hand rule applies, and why?
- 6
A wire is moved downward through a magnetic field directed from left to right. An emf is induced in the wire. Which hand rule should be used to determine the current direction?
- 7
A straight wire carries conventional current upward. You want to find the direction of the magnetic field that circles around the wire. Which rule should you use?
- 8
A student is given a diagram of a generator and uses Fleming's left-hand rule to find the induced current. Identify the mistake and correct it.
- 9
A current in a wire points east, and the magnetic field points north. The question asks for the direction of the force on the wire. Which rule applies?
- 10
A metal rod slides to the right across two conducting rails in a magnetic field. The motion creates a current in the circuit. Which hand rule applies?
- 11
Complete the comparison: Fleming's left-hand rule is mainly for motors because it finds the direction of blank. Fleming's right-hand rule is mainly for generators because it finds the direction of blank.
- 12
A problem describes a loudspeaker coil carrying an alternating current in a magnetic field. The coil moves back and forth to vibrate the speaker cone. Which hand rule is used to predict the force direction at an instant?