Faraday and Lenz

A student moves a magnet into a coil of wire as shown in the diagram. The coil of wire is connected to a sensitive ammeter.

• increasing the number of turns on the coil

• increasing the speed of the magnet

• increasing the strength of the magnet

• all of the above

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

A flat coil consists of 20 turns each of area

an area of 50 cm2, is positioned perpendicularly to a uniform magnetic field that increases its magnitude at a constant rate from 2.0 T to 6.0 T in 2.0 s. If the coil has a total resistance of 0.40 ohms , what is the magnitude of the induced current?

• 70 mA

• 140 mA

• 500 mA

• 800 mA

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

A loop of wire is placed near a current carrying wire as shown below. Which of the following actions will NOT produce an induced current in the loop?

• Moving the loop towards the wire

• Moving the loop away from the wire

• Moving the loop parallel to the wire

• Increasing the electric current in the wire

Tags

NGSS.HS-PS2-5

A circular conducting loop is in a region of magnetic field B directed out of the page, as shown below. The magnitude of the magnetic field is decreasing. The direction of the induced current in the loop is

• Clockwise

• counterclockwise

• Undefined because the current is zero

• Impossible to determine without knowing the rate of change of field

Tags

NGSS.HS-PS2-5

According to Lenz’s law the direction of an induced current in a conductor will be that which tends to produce which of the following effects?

• enhance the effect which produces it

• produce a greater heating effect

• produce the greatest voltage

• oppose the effect which produces it

The long straight wire in the figure carries a current I that is decreasing with time at a constant rate. The circular loops A, B, and C all lie in a plane containing the wire. The induced emf in each of the loops A, B, and C is such that

• no emf is induced in any of the loops

• a counterclockwise emf is induced in all the loops

• loop A has a counter-clockwise emf, loop B has no induced emf, and loop C has a clockwise emf

• loop A has a counter-clockwise emf, loops B and C have clockwise emfs

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

A rectangular conducting loop is placed near a long wire carrying a current P as shown in the figure below. If I decreases in time, what can be said of the current induced in the loop?

• The direction of the current depends on the size of the loop

• The current is counterclockwise

• The current is clockwise

• The current is zero

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

A circuit containing only a lightbulb is placed in a uniform magnetic field B directed into the page, as shown below on the left. The variation of the magnetic field as a function of time is shown in the graph. the time interval in which the bulb will be brightest

• 0-2 s

• 2-4 s

• 4-6 s

• 6-8 s

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

A conducting ring is moving from left to right through a region that contains a constant magnetic field as shown in the diagram. In which region is there an induced current in the ring?

• A and E

• B and D

• B,C and D

• A,B,C and D

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

The three loops of wire shown in the figure are all subject to the same uniform magnetic field B that does not vary with time. Loop 1 oscillates back and forth as the bob in a pendulum, loop 2 rotates about a vertical axis, and loop 3 oscillates up and down at the end of a spring. Which loop, or loops, will have an emf induced in them?

• loop 1 only

• loop 2 only

• loop 3 only

• loops 1 and 2

Tags

NGSS.HS-PS2-5