21.1 - Inducing Currents

In the figure below, if the wire were moved to the left instead of the right, what would the direction of the magnetic force on it be?

• into the page

• down

• up

• out of the page

A 0.30-m long straight wire moves at a constant speed of 9.5 m/s perpendicular to a magnetic field of strength 0.083 T. What EMF is induced in the wire?

• 0.48 V

• 1.2 V

• 2.6 V

• 0.24 V

A wire 15 m long moves through a magentic field of 1.0 T. The wire moves at a constant speed of 5.7 m/s in a direction perpendicular to the magnetic field. What EMF is induced in the wire?

• 2.6 V

• 86 V

• 43 V

• 61 V

A changing magnetic field can produce a(n)__________.

• electric current

• resistor

• spark of electricity

• force

What is the unit for EMF?

• C/J

• V

• N

• N.m

You want to generate an EMF of 2.6 V by moving a wire at 3.0 m/s through a 0.040-T magnetic field. If you keep the wire perpendicular to the magnetic field, what length of wire should you use?

• 22 m

• 0.035 m

• 0.046 m

• 11 m

__________ is the generation of current due to relative motion between a wire and a magnetic field.

• Magnetic flux

• Electromagnetic induction

• Electrolysis

• Electrospectrometry

If a wire moves through a magnetic field at an angle to the field, only the component of the wire’s velocity that is _____ generates EMF.

• If a wire moves through a magnetic field at an angle to the field, only the component of the wire’s velocity that is _____ generates EMF.

• parallel to the direction of the magnetic field

• perpendicular to the direction of the magnetic field

• positive

The EMF produced in a wire moving in a magnetic field depends on _____.

• only the current in the wire

• only the magnetic field strength

• only the magnetic field strength, the length of the wire in the field, and the direction the wire moves

• the magnetic field strength, the length of the wire in the field, and the velocity of the wire