Electromagnetic Induction Practice Problems-2009!05!13

5/21/2018 Electromagnetic Induction Practice Problems-2009!05!13

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Electromagnetic InductionPractice Problems HomeworkPSI AP Physics B Name___________________________________

Multiple Choice Questions

1. A square loop of wire is placed in a uniform magnetic field perpendicular to the magnetic

lines. The strength of the magnetic field is 0.5 T and the side of the loop is 0. m. !hat

is the magnetic flu" in the loop#

A$ 0.0 !% &$ 0.0' !% C$ 0.0( !% )$ 0.0* !% +$ 0.10 !%

. A circular loop of wire is placed in a uniform magnetic field perpendicular to the magnetic

lines. The strength of the magnetic field is & and the radius of the loop is ,. !hat is the

magnetic flu" in the loop#

A$ - &, &$ - &, C$ - &, )$ - &, +$ &,


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/. A square loop of wire with one side of 0.' m is placed in a uniform magnetic field & T.

The normal line to the loop maes ( with the magnetic field lines. !hat is the magnetic0

flu" in the loop#

A$ 0.1 !% &$ 0.1' !% C$ 0.1( !% )$ 0.1* !% +$ 0.0 !%

'. A circular loop is initiall2 placed in a uniform magnetic field perpendicular to the fieldlines and then remo3ed quicl2 from the field. The induced emf causes the electric

charge flow in the loop. !hich of the following e"plains the force on the induced current

due to the original field#

A$ 4orce causes the loop to turn around its a"is

&$ 4orce causes the loop to turn around its diameter

C$ 4orce causes the loop to accelerate in the field direction

)$ 4orce causes the loop to accelerate perpendicular to the field direction

+$ 4orce opposes to an2 motion of the loop

5. A magnet %ar with the north pole down is held a%o3e a

horiontal aluminum ring. !hich of the following is true

a%out the induced current in the ring# 67iew from a%o3e$

A$ There is no current in the ring

&$ There is a clocwise current in the ring

C$ There is a counterclocwise current in the ring

)$ There is an AC current in the ring

+$ More information is required


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(. A magnet %ar with the north pole down is held a%o3e a

horiontal aluminum ring. !hich of the following is true

a%out the induced current in the ring# 67iew from a%o3e$

A$ There is no current in the ring

&$ There is a clocwise current in the ring

C$ There is a counterclocwise current in the ring

)$ There is an AC current in the ring


8. A circular loop of wire is placed in a uniform magnetic field directed out of the page.

9uddenl2 the magnetic field disappears. !hat is the direction of the induced current in

the loop#

A$ Clocwise &$ Counterclocwise C$ No current in the coil

)$ :nto the page +$ ;ut of the page

*. A square loop of wire is placed in a uniform magnetic field directed into the page.

9uddenl2 the magnetic field grows stronger. !hat is the direction of the induced current

in the loop#

A$ Clocwise &$ Counterclocwise C$ No current in the coil

)$ :nto the page +$ ;ut of the page


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oint M is at higher potential

&$ >oint = is at higher potential

C$ >otential is higher at the surface of the rod

)$ >otential is higher at the center of the rod


10. A copper rod M= mo3es at a constant speed in a uniform magnetic field perpendicular to

the magnetic lines. !hich statement is true a%out the electric potential in the rod#

A$ >oint M is at higher potential

&$ >oint = is at higher potential

C$ >otential is higher at the surface of the rod

)$ >otential is higher at the center of the rod



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11. A square loop of wire with one side of a and resistance , is pulled out the field with a

constant speed of 3. The strength of the field is &. !hich statement is true a%out the

magnitude and direction of the induced current#

Magnitude )irection

A$ &a3, Counterclocwise

&$ &a3, Clocwise

C$ &a3, Counterclocwise

)$ &a3, Clocwise

+$ &a3, Counterclocwise

1. A square loop of wire with one side of a and resistance , is pulled out the field with a

constant speed of 3. The strength of the field is &. !hich statement is true a%out the

magnitude and direction of the magnetic force on the loop#

6A$ &a3, :n the direction of the loop?s motion

6&$ &a3, :n opposite direction to the loop?s motion

6C$ &a3, :n the direction of the loop?s motion

6)$ &a3, :n opposite direction to the loop?s motion

6+$ &a3, :n the direction of the loop?s motion


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1/. A square loop of aluminum wire is initiall2 placed perpendicular to the lines of a constant

magnetic field of 0.5 T. The area enclosed %2 the loop is 0. m. The loop is then turned

through an angle of


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1(. A loop of wire is pulled with constant 3elocit2 3 to the right through a region of space

where there is a uniform magnetic field & directed into the page as shown a%o3e. The

magnetic force on the loop is

A$ )irected to the left %oth as it enters and as it lea3es the region

&$ )irected to the right %oth as it enters and as it lea3es the region

C$ )irected to the left as it enters the region and to the right as it lea3es

)$ )irected to the right as it enters the region and to the left as it lea3es

+$ ero at all times

18. A 3ertical length of copper wire mo3es to the right with a constant speed 3 in the

perpendicular direction of a constant horiontal magnetic field &. !hich of the following

descri%es the induced charges on the ends of the

wire#

>oint M >oint =

A$ >ositi3e Negati3e

&$ Negati3e >ositi3e

C$ Negati3e Bero

)$ Bero Negati3e

+$ Bero Bero


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1*. !hen the switch is closed the direction of the electric

current is

=oop 1 =oop

6A$ Clocwise Counterclocwise

6&$ Counterclocwise Clocwise

6C$ Clocwise Clocwise

6)$ Counterclocwise Counterclocwise

6+$ Bero Bero

1


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0. A magnet %ar with a north pole down is dropped from a certain height and on the wa2

down passes through a closed coil of wire. !hich statement is true a%out the magnet?s

acceleration#

6A$ Dreater than g &$ =ess than g C$ g )$ Bero acceleration



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4reeE,esponse >ro%lems

1. A 0. F rectangular loop of wire has an area of 0.5 m and placed in a region where

magnetic field changes as shown on the diagram.

a. !hat is the magnetic flu" in the loop at 0.' s#

%. !hat is the induced emf for the following time#

i. _______ 0.1 s ii. ________0./ s iii. ________ 0.5 s

c. !hat is the induced current for the following time#

i. _______ 0.1 s ii. ________0./ s iii. ________ 0.5 s

d. ;n the diagram %elow graph the induced current as a function of time.


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. A rectangular loop of wire 0.5 m wide and 1.5 m long is mo3ing out of a uniform

magnetic field & T at a constant speed of ms. The left side of the loop sta2s

inside the field when the right side is out. The resistance of the loop is 0.5 F.

a. !hat is the direction of the induced current in the loop#

%. Calculate the induced emf in the loop.

c. Calculate the induced current in the loop.

d. Calculate the applied force required to mo3e the loop at the constant

speed.

e. Calculate the power de3eloped %2 the force.


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/. A metallic rod has a length = and slides at a constant speed 3 on the top of two

conducting parallel rails. The rails are connected to a resistor ,. The apparatus is

placed in a uniform magnetic field & which is perpendicular to the plane where

rod is mo3ing.

a. !hat is the direction of the induced current#

%. )etermine the induced emf.

c. )etermine the induced current in the circuit.

d. )etermine the electric field + induced in the rod.

e. )etermine the force required to mo3e the rod at the constant speed.

f. )etermine the power dissipated in the resistor when the rod crosses the

magnetic field.


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'. A coil /0 cm in diameter consist of 0 turns of circular copper wire mm in

diameter. The coil is connected to a low resistance gal3anometer. :nitiall2 coil is

placed in a uniform magnetic field perpendicular to its plane. )uring the

e"periment the magnetic field changes from 0.5 T to .5 T in 0.' s. :gnore the

resistance of the connecting wires.6copper resisti3it2 1.(*G10E*FGm$

a. Calculate the initial flu" in the coil.

%. Calculate the induced emf in the gal3anometer.

c. Calculate the induced current in the coil.

d. Calculate the power dissipated in the coil as the field changes.


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Multiple Choice Answers

1. +. &/. C'. +

5. A(. H8. &*. &


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.a. Counter clocwise%. 7c. ' Ad. ' Ne. * !

/.a. Counter clocwise%. I &=3c. : &=3,d. + &3e. 4 &=3,f. > &=3,

'.a. 0.81 !%. 0.< 7c. 0.0*'1 Ad. 0.0858 !

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Electromagnetic Induction Practice Problems-2009!05!13