8/12/2019 Physics 2 - CH28-31 Test 3

1/17

Name: __________________________ Date: _____________

1. In the formula :F qv B=

A) F must be perpendicular to v but not necessarily to B

B) F must be perpendicular to B but not necessarily to v

C) v must be perpendicular to B but not necessarily to FD) all three vectors must be mutually perpendicular

) F must be perpendicular to both andv B

!. A ma"netic field e#erts a force on a char"ed particle:A) al$ays

B) never

C) if the particle is movin" across the field lines

D) if the particle is movin" alon" the field lines) if the particle is at rest

%. An electron &char"e ' (1. 1*(1+C) is movin" at % 1*,m-s in the positivex

direction. A ma"netic field of *. / is in the positivezdirection. /he ma"netic force on

the electron is:A) *

B) 0 1*(10N in the positivezdirection

C) 0 1*(10N in the ne"ativezdirection

D) 0 1*(10N in the positiveydirection

) 0 1*(10N in the ne"ativeydirection

0. An electron travels due north throu"h a vacuum in a re"ion of uniform ma"netic field Bthat is also directed due north. It $ill:

A) be unaffected by the fieldB) speed up

C) slo$ do$n

D) follo$ a ri"hthanded cor2scre$ path) follo$ a lefthanded cor2scre$ path

,. A uniform ma"netic field is in the positivezdirection. A positively char"ed particle ismovin" in the positivexdirection throu"h the field. /he net force on the particle can be

made 3ero by applyin" an electric field in $hat direction4

A) 5ositiveyB) Ne"ativey

C) 5ositivex

5a"e 1

8/12/2019 Physics 2 - CH28-31 Test 3

2/17

D) Ne"ativex

) 5ositivez

. 6. 6. /homson7s e#periment8 involvin" the motion of an electron beam in mutually

perpendicular andE B fields8 "ave the value of:A) mass of electron

B) char"e of electron

C) arth7s ma"netic fieldD) char"e-mass ratio for electron

) Avo"adro7s number

9. An electron and a proton are both initially movin" $ith the same speed and in the same

direction at +* to the same uniform ma"netic field. /hey e#perience ma"netic forces8$hich are initially:

A) identicalB) e;ual in ma"nitude but opposite in direction

C) in the same direction and differin" in ma"nitude by a factor of 10*D) in opposite directions and differin" in ma"nitude by a factor of 10*

) e;ual in ma"nitude but perpendicular to each other

. A cyclotron operates $ith a "iven ma"netic field and at a "iven fre;uency. IfRdenotes

the radius of the final orbit8 the final particle ener"y is proportional to:A) 1-R

B) R

C) R!

D) R%

) R0

+. /he fi"ure sho$s a uniform ma"netic field B directed to the left and a $ire carryin" a

current into the pa"e. /he ma"netic force actin" on the $ire is:

A) to$ard the top of the pa"eB) to$ard the bottom of the pa"e

C) to$ard the left

D) to$ard the ri"ht) 3ero

5a"e !

8/12/2019 Physics 2 - CH28-31 Test 3

3/17

1*. A loop of $ire carryin" a current of !.* A is in the shape of a ri"ht trian"le $ith t$oe;ual sides8 each 1, cm lon". A *.9 / uniform ma"netic field is in the plane of the

trian"le and is perpendicular to the hypotenuse. /he resultant ma"netic force on the t$o

sides has a ma"nitude of:A) *

B) *.!1 N

C) *.%* ND) *.01 N

) *.,1 N

11. A circular loop of $ire $ith a radius of !* cm lies in thexyplane and carries a current of

! A8 countercloc2$ise $hen vie$ed from a point on the positiveza#is. Its ma"netic

dipole moment is:

A) *.!, A m!

8 in the positivezdirectionB) *.!, A m!8 in the ne"ativezdirection

C) !., A m!8 in the positivezdirection

D) !., A m!8 in the ne"ativezdirection

) *.!, A m!8 in thexyplane

1!. /he dia"rms sho$ five possible orientations of a ma"netic dipole in a uniform

ma"netic field .B

8/12/2019 Physics 2 - CH28-31 Test 3

4/17

) (1.* 1*(%6

10. >uitable units for *are:

A) tesla

B) ne$ton-ampere!C) $eber-meterD) 2ilo"ramampere-meter

) teslameter-ampere

1,. In the fi"ure8 the current element d 8i l the point 58 and the three vectors &18 !8 %) are all

in the plane of the pa"e. /he direction of d 8B due to this current element8 at the point 5

is:

A) in the direction mar2ed ?1?

B) in the direction mar2ed ?!?

C) in the direction mar2ed ?%?D) out of the pa"e

) into the pa"e

1. /he ma"netic field a distance ! cm from a lon" strai"ht currentcarryin" $ire is ! 1*(,

/. /he current in the $ire is:

A) *.1 AB) 1.* A

C) !.* A

D) 0.* A

) !, A

19. /$o lon" strai"ht $ires are parallel and carry current in opposite directions. /hecurrents are .* A and 1! A and the $ires are separated by *.0* cm. /he ma"netic field

in tesla at a point mid$ay bet$een the $ires is:

A) *B) 0.* 1*(0

C) .* 1*(0

D) 1! 1*(0

5a"e 0

8/12/2019 Physics 2 - CH28-31 Test 3

5/17

) !* 1*(0

1. /he dia"ram sho$s three e;ually spaced $ires that are perpendicular to the pa"e. /he

currents are all e;ual8 t$o bein" out of the pa"e and one bein" into the pa"e. @an2 the

$ires accordin" to the ma"nitudes of the ma"netic forces on them8 from least to"reatest.

A) 18 !8 %B) !8 1 and % tie

C) ! and % tie8 then 1

D) 1 and % tie8 then !) %8 !8 1

1+. /$o parallel $ires8 0 cm apart8 carry currents of ! A and 0 A respectively8 in the same

direction. /he force per unit len"th in N-m of one $ire on the other is:

A) 1 1*(%8 repulsive

B) 1 1*(%8 attractive

C) 0 1*(,8 repulsive

D) 0 1*(,8 attractive

) none of these

!*. In Ampere7s la$8 * 8B d s i = the inte"ration must be over any:A) surfaceB) closed surface

C) path

D) closed path) closed path that surrounds all the current producin" B

!1. /$o lon" strai"ht $ires enter a room throu"h a $indo$. ne carries a current of %.* A

into the room $hile the other carries a current of ,.* A out. /he ma"nitude in /m of the

path inte"ral B d s around the $indo$ frame is:A) !., 1*( / m

B) %. 1*(/ m

C) .% 1*( / m

D) 1.* 1*(, / m

) none of these

5a"e ,

8/12/2019 Physics 2 - CH28-31 Test 3

6/17

!!. /he ma"netic fieldBinside a lon" ideal solenoid is independent of:

A) the current

B) the core materialC) the spacin" of the $indin"s

D) the crosssectional area

) the direction of the current

!%. In the e#periment sho$n:

A) there is a steady readin" in as lon" as > is closed

B) a motional emf is "enerated $hen > is closed

C) the current in the battery "oes throu"h D) there is a current in ust after > is opened or closed

) since the t$o loops are not connected8 the current in is al$ays 3ero

!0. A !/ uniform ma"netic field ma2es an an"le of %*$ith theza#is. /he ma"netic flu#

throu"h a %m!portion of thexyplane is:

A) !.* bB) %.* b

C) ,.! b

D) b

) 1! b

!,. 1 $eber is the same as:

A) 1 =-s

B) 1 /-sC) 1 /-m

D) 1 / m!

) 1 /-m!

!. In the circuit sho$n8 there $ill be a non3ero readin" in "alvanometer :

A) only ust after > is closed

5a"e

8/12/2019 Physics 2 - CH28-31 Test 3

7/17

B) only ust after > is opened

C) only $hile > is 2ept closed

D) never) only ust after > is opened or closed

!9. A rectan"ular loop of $ire has area A. It is placed perpendicular to a uniform ma"netic

fieldBand then spun around one of its sides at fre;uencyf./he ma#imum induced emf

is:A) BAf

B) !BAf

C) !BAf

D) 0BAf

!. A copper hoop is held in a vertical east$est plane in a uniform ma"netic field $hose

field lines run alon" the northsouth direction. /he lar"est induced emf is produced$hen the hoop is:

A) rotated about a northsouth a#is

B) rotated about an east$est a#isC) moved rapidly8 $ithout rotation8 to$ard the east

D) moved rapidly8 $ithout rotation8 to$ard the south

) moved rapidly8 $ithout rotation8 to$ard the north$est

!+. A sin"le loop of $ire $ith a radius of 9., cm rotates about a diameter in a uniform

ma"netic field of 1. /. /o produce a ma#imum emf of 1.* =8 it should rotate at:

A) *B) !.9 rad-s

C) ,. rad-sD) %, rad-s

) 91 rad-s

%*. As a loop of $ire $ith a resistance of 1* moves in a constant nonuniform ma"netic

field8 it loses 2inetic ener"y at a uniform rate of , m6-s. /he induced current in the loop:A) is *

B) is ! mA

C) is !. mAD) is !* mA) cannot be calculated from the "iven data

5a"e 9

8/12/2019 Physics 2 - CH28-31 Test 3

8/17

%1. A rod $ith resistanceRlies across frictionless conductin" rails in a constant uniform

ma"netic fieldB8 as sho$n. Assume the rails have ne"li"ible resistance. /he ma"nitude

of the force that must be applied by a person to pull the rod to the ri"ht at constant speedvis:

A) *

B) BLvC) BLv-R

D) B!L!v-R

) B!Lxv-R

%!. A lon" strai"ht $ire is in the plane of a rectan"ular conductin" loop. /he strai"ht $ire

carries a constant current i8 as sho$n. hile the $ire is bein" moved to$ard therectan"le the current in the rectan"le is:

A) 3ero

B) cloc2$ise

C) countercloc2$iseD) cloc2$ise in the left side and countercloc2$ise in the ri"ht side

) countercloc2$ise in the left side and cloc2$ise in the ri"ht side

%%. /he fi"ure sho$s a bar movin" to the ri"ht on t$o conductin" rails. /o ma2e an induced

current iin the direction indicated8 a constant ma"netic field in re"ion A should be in

$hat direction4

A) @i"ht

B) Eeft

5a"e

8/12/2019 Physics 2 - CH28-31 Test 3

9/17

C) Into the pa"e

D) ut of the pa"e

) Impossible8 cannot be done $ith a constant ma"netic field

%0. A cylindrical re"ion of radius @ ' %.* cm contains a uniform ma"netic field parallel toits a#is. If the electric field induced at a point @-! from the cylinder a#is 0., 1*%v-m

the ma"itude of the ma"netic field must be chan"in" at the rate:

A) *B) *.%* /-s

C) *.* /-s

D) 1.! /-s) !.0 /-s

%,. /he unit ?henry? is e;uivalent to:

A) voltsecond-ampereB) volt-second

C) ohm

D) amperevolt-second

) amperesecond-volt

%. A 1*turn ideal solenoid has an inductance of %., mF. hen the solenoid carries acurrent of !.* A the ma"netic flu# throu"h each turn is:

A) *

B) %., 1*(0$b

C) 9.* 1*(0$b

D) 9.* 1*(%$b

) 9.* 1*(!$b

%9. A lon" narro$ solenoid has len"th l and a total ofNturns8 each of $hich has crosssectional areaA. Its inductance is:

A) !*N A l

B) !*

-N A l

C)*

-NA l

D) !*

-N A l

) none of these

5a"e +

8/12/2019 Physics 2 - CH28-31 Test 3

10/17

%. An .*mF inductor and a !.*resistor are $ired in series to an ideal battery. A s$itch

in the circuit is closed at time *8 at $hich time the current is *. /he current reaches half

its final value at a time of:A) !. ms

B) 0.* ms

C) % sD) 19* s

) !,* s

%+. An .*mF inductor and a !.*resistor are $ired in series to a !*= ideal battery. A

s$itch in the circuit is closed at time *8 at $hich time the current is 3ero. Immediately

after the s$itch is thro$n the potential differences across the inductor and resistor are:A) *8 !* =

B) !* =8 *

C) 1* =8 1* =

D) 1 =8 0 =) un2no$n since the rate of the current is not "iven

0*. A %., mF inductor and a 0., mF inductor are connected in series. /he e;uivalent

inductance is:

A) !.* mFB) *.,1 mF

C) *.1% mF

D) 1.* mF

) .* mF

01. A %., mF inductor and a 0., mF inductor are connected in parallel. hen the total emfof the combination is 1 =8 the rate of chan"e of the current in the lar"er inductor is:

A) !.* 1*%A-s

B) %. 1*%A-s

C) 0. 1*%A-s

D) 9.* 1*%A-s

) .1 1*%A-s

0!. A current of 1* A in a certain inductor results in a stored ener"y of 0* 6. hen the

current is chan"ed to , A in the opposite direction8 the stored ener"y chan"es by:

A) !* 6B) %* 6

C) 0* 6

D) ,* 6

) * 6

5a"e 1*

8/12/2019 Physics 2 - CH28-31 Test 3

11/17

0%. A .* mF inductor is in a circuit. At the instant the current is ,.* A and its rate of chan"e

is !** A-s8 the rate $ith $hich the ener"y stored in the inductor is increasin" is:A) 9., 1*(!

B) 1!*

C) !0* D) %.*

) .*

00. /he ;uantity &B!-o) has units of:

A) 6

B) 6-FC) 6-m

D) 6-m%

) F-m%

0,. A *.!*cm radius cylinder8 %.* cm lon"8 is $rapped $ith $ire to form an inductor. At the

instant the ma"netic field in the interior is ,.* m/ the ener"y stored in the field is:A) *

B) %. 1*(6

C) 9., 1*(6

D) 9., 1*(0 6

) +.+ 6

0. A char"ed capacitor and an inductor are connected in series. At time t' * the current is3ero8 but the capacitor is char"ed. If T is the period of the resultin" oscillations8 the ne#t

time8 after t' * that the char"e on the capacitor is a ma#imum is:

A) TB) T-0

C) T-!

D) !T

09. A 1,*" bloc2 on the end of a sprin" $ith a sprin" constant of %, N-m is pulled aside !,cm and released from rest. In the electrical analo" the initial char"e on the capacitor is:

A) *.1, CB) .9 C

C) *.*!, CD) 0* C

) %, C

5a"e 11

8/12/2019 Physics 2 - CH28-31 Test 3

12/17

0. e desire to ma2e anLCcircuit that oscillates at 1** F3 usin" an inductance of !., F.

e also need a capacitance of:

A) 1