CHAPTER 7 TUTORIAL

The magnetic field oriented into the page has an initial field strength of 5 Tesla into the page. It changes to 2 Tesla into the page. What is the direction of the induced current?

• CW

• CCW

Magnetic flux is measured in

• teslas

• coulombs

• webers

• farads

A conductive loop moves downward into the magnetic field as shown in the diagram. Which way will the induced current flow in the conductive loop?

• CW

• CCW

Can you produce current in a wire with a magnet that is sitting still?

• Yes; having a magnet near a wire is enough to excite the electrons

• No; the magnetic field has to be changing to excite the electrons

• No; magnets cannot create electricity

If you wrap more coils around an electromagnet, it will become...

• brighter
• stronger
• weaker
• invisible

A magnet can move in a coil of wire to produce electricity in which system?

• Generator
• Motor
• Magnet
• Transformer

What is the direction of the induced magnetic field?

• Left
• Right
• Up
• Down

Magnetic flux is related to magnetic field strength by the formula

• Φ=BA

• Φ=BA²

• Φ=B/A

• Φ=B/A²

A coil of wire (N = 40) carries a current of 2 A and has a radius of 6 cm. The current is decreased at 0.1 A/s. Inside this coil is another coil of wire (N = 10 and r = 3 cm) aligned so that the faces are parallel. What is the average emf induced in the smaller coil during 5 s?

• 6.28x10^-6 V

• 2.37x10^-6 V

• 1.18x10^-6 V

• 1.78x10^-6 V

• 0.4 volt

• -0.4 volt

• -2 volt

• 2 volt