Physics Electromagnetism Practice Test             Name __________________

Multiple Choice
Identify the choice that best completes the statement or answers the question.

____	1.	Two charges separated by a distance of 1 meter exert a 20-N force on each other. If the charges are pulled to a 2 meter separation distance, the force on each charge will be 
a.	0 N.	
b.	5 N.	
c.	10 N.	
d.	40 N.	
e.	80 N.	

____	2.	The SI unit of charge is the 
a.	ohm.	
b.	joule.	
c.	coulomb.	
d.	ampere.	
e.	newton.	

____	3.	Two charges, of 0.00038 C and 0.000068 C, are located 3 m apart.  Find the electrical force between them.
a.	26 N	c.	2.9 E -9 N	
b.	78 N	d.	14 N	

____	4.	Two charged particles held near each other are released. As they move, the acceleration of each increases. Therefore, the particles have 
a.	opposite signs.	
b.	the same sign.	
c.	charges that can not be determined.	

____	5.	A negatively charged rod is brought near a metal can that rests on a wood table. You touch the opposite side of the can momentarily with your finger. The can is then 
a.	positively charged.	
b.	negatively charged.	
c.	charged the same as it was.	
d.	uncharged.	

____	6.	To say that electric charge is conserved means that no case has ever been found where 
a.	the total amount of charge on an object has increased.	
b.	one object has more charge than another object.	
c.	the total charge on an object has changed.	
d.	net charge has been created or destroyed.	

____	7.	If you comb your hair and the comb becomes negatively charged, your hair becomes 
a.	uncharged.	
b.	positively charged.	
c.	negatively charged.	

____	8.	
What charge will end up on sphere B?
a.	negative	c.	neutral	
b.	positive	

____	9.	
In what direction will an electron move if placed in the middle of the diagram?

a.	To the right.	c.	The electron will not move.	
b.	To the left.	

____	10.	An ampere is a 
a.	unit of resistance.	
b.	unit of current.	
c.	type of charge.	
d.	voltage.	
e.	current.	

____	11.	Electrical resistance is measured in 
a.	volts.	
b.	amperes.	
c.	joules.	
d.	watts.	
e.	none of the above.	

____	12.	A circuit has a potential difference of 100 V, and the current is 20 A.  What is the resistance of the circuit?
a.	5 Ohms	c.	80 Ohms	
b.	120 Ohms	d.	2,000 Ohms	

____	13.	A 25-ohm resistor has a 3-A current in it. What is the voltage across the resistor?
a.	75 V	
b.	8.3 V	
c.	22 V	
d.	28 V	

____	14.	When connected to a 110-volt power supply, how much current is in a light bulb that has a resistance of 220 ohms?
a.	0.5 A	
b.	2.0 A	
c.	110 A	
d.	220 A	
e.	24,200 A	

____	15.	How much power is used by a 12.0-V car battery that draws 0.5 A of current?
a.	0.5 W	
b.	6 W	
c.	12 W	
d.	24 W	
e.	30 W	

____	16.	As more lamps are put into a parallel circuit, the overall current in the circuit 
a.	increases.	
b.	stays the same.	
c.	decreases.	

____	17.	When one light bulb in a parallel circuit containing several light bulbs burns out, the other light bulbs 
a.	do not burn at all.	
b.	burn the same as before.	

____	18.	The total resistance of a 4-ohm resistor and a 12-ohm resistor in series is 
a.	48 ohms.	
b.	16 ohms.	
c.	3 ohms.	
d.	8	

____	19.	When plugged into a 120-V wall outlet, how much current is used by an electric blanket rated at 140 W?
a.	16,800 A	
b.	140 A	
c.	120 A	
d.	1.2 A	
e.	none of the above	

____	20.	A light bulb is plugged into a 120-volt outlet and has a 0.7 A current in it. What is the power rating of the light bulb?
a.	12 W	
b.	17 W	
c.	84 W	
d.	120 W	
e.	171 W	

____	21.	A power line with a resistance of 20 ohms has a current of 30 A in it. The power dissipated in the line is 
a.	600 W.	
b.	18,000 W.	
c.	50 W.	
d.	27,000 W.	

____	22.	Changing the magnetic field intensity in a closed loop of wires induces 
a.	current.	
b.	voltage.	
c.	both current and voltage.	
d.	neither current nor voltage.	

____	23.	Electric current can best be induced in a wire by 
a.	stretching the wire.	
b.	moving a magnet up and down near the wire.	
c.	setting the wire near a magnet.	
d.	rotating the wire.	
e.	none of the above	

____	24.	A magnet is moved in and out of a coil of wire connected to several lamps. If the number of coils is halved
a.	it is easier to move the magnet.	
b.	there is no difference in moving the magnet.	
c.	it is harder to move the magnet.	

____	25.	If a magnet is pushed into a coil, voltage is induced across the coil. If the same magnet is pushed into a coil with a lower speed 
a.	a larger voltage is induced.	
b.	a smaller voltage is induced.	
c.	the same voltage is induced.	

____	26.	A transformer transforms 
a.	magnetic field lines.	
b.	generators into motors.	
c.	voltage.	
d.	unsafe forms of energy into safe forms. 

____	27.	The primary coil of a transformer has 100 turns on it and the secondary coil has 50 turns on it. This is 
a.	a step-down transformer.	
b.	a step-up transformer.	
c.	either of the above, depending on relative input and output currents	

____	28.	The voltage across a transformer primary coil that has 50 turns is 25 V. What is the voltage across the secondary coil, which has 20 turns?
a.	2 V	
b.	10 V	
c.	20 V	
d.	40 V	
e.	50 V

____	29.	The voltage across the input terminals of a transformer is 140 V. The primary has 20 loops and the secondary has 10 loops. The voltage the transformer puts out is 
a.	10 V.	
b.	70 V.	
c.	140 V.	
d.	280 V.	
e.	none of the above

____	30.	The induced voltage in a coil is proportional to
a.	the number of loops.	
b.	the radius of the loops.	
c.	the height of the coil.	
d.	all of the above.	

____	31.	
In the diagram, R1 is 15 Ohms and R2 is 5 Ohms.  If the current through segment 2 of the wire is 3 A, what is the current through segment 3?
a.	1 A	c.	3 A	
b.	2 A	d.	9 A	

____	32.	In the above diagram, R1 is 12 Ohms and R2 is 18 Ohms.  What is the total resistance in the circuit?
a.	1.5 Ohms	c.	6 Ohms	
b.	30 Ohms	d.	7.2 Ohms	

____	33.	In the above diagram, the resistance of R1 is 13 Ohms and R2 is 17 Ohms.  If a multimeter reads the current at segment 3 as 3.4 A, what is the potential difference across the battery?
a.	17 V	c.	25 V	
b.	256 V	d.	102 V	

____	34.	In the diagram above, the battery produces 30 V.  If the current at segment 1 is 3 A, R1 is 4 Ohms and R2 is 6 Ohms, what is the voltage across R2?
a.	10 V	c.	6 V	
b.	18 V	d.	12 V

____	35.	

In the diagram above, the total voltage across the battery is 40 V.  R1 is 6 Ohms and R2 is 10 Ohms.  If the current through segment 1 of the circuit is 10.7 A, what is the voltage across R1?
a.	64.2 V	c.	24 V	
b.	40 V	d.	5 V	

____	36.	In the diagram above, the battery is 60 V, R1 is 20 Ohms and R2 is 5 Ohms.  What is the total resistance of the circuit?
a.	4 Ohms	c.	12.5 Ohms	
b.	25 Ohms	d.	15 Ohms	

____	37.	In the diagram above, the battery is 80 V, R1 is 4 Ohms and R2 is 8 Ohms.  What is the current through R2?
a.	10 A	c.	20 A	
b.	6.7 A	d.	30 A	

____	38.	In the diagram above, the battery is 70 V, R1 is 8 Ohms and R2 is 12 Ohms.  What is the total current in the circuit?
a.	5 A	c.	3.5 A	
b.	18.6 A	d.	14.6 A

____	39.	How many 3-Ohm resistors must be connected in parallel to create a total resistance of 1 Ohm?
a.	1	c.	3	
b.	2	d.	6	

____	40.	What is the total resistance of a 4-Ohm resistor and a 12-Ohm resistor in parallel?
a.	16 Ohms	c.	0.33 Ohms	
b.	8 Ohms	d.	3 Ohms	

Physics Electromagnetism Practice Test             Name __________________
Answer Section

MULTIPLE CHOICE

	1.	ANS:	B	PTS:	1	DIF:	L2	OBJ:	32.3 Coulomb's Law
STA:	Ph.1.m	KEY:	charge | distance		BLM:	application

	2.	ANS:	C	PTS:	1	DIF:	L1	OBJ:	32.3 Coulomb's Law
STA:	Ph.1.m	KEY:	unit | charge	BLM:	knowledge

	3.	ANS:	A	PTS:	1

	4.	ANS:	A	PTS:	1	DIF:	L2	OBJ:	32.3 Coulomb's Law
STA:	Ph.1.m	KEY:	charge | acceleration		BLM:	analysis

	5.	ANS:	A	PTS:	1	DIF:	L2	OBJ:	32.6 Charging by Induction
STA:	Ph.5.e	KEY:	induction | positive | negative	BLM:	analysis

	6.	ANS:	D	PTS:	1	DIF:	L2	OBJ:	32.2 Conservation of Charge
STA:	Ph.5.e | Ph.5.k			KEY:	charge | net	BLM:	comprehension

	7.	ANS:	B	PTS:	1	DIF:	L2	
OBJ:	32.5 Charging by Friction and Contact		STA:	Ph.5.e
KEY:	comb | charge			BLM:	application

	8.	ANS:	A	PTS:	1

	9.	ANS:	A	PTS:	1

	10.	ANS:	B	PTS:	1	DIF:	L1	OBJ:	34.2 Electric Current
STA:	Ph.5.a | Ph.5.e			KEY:	ampere | unit		
BLM:	knowledge

	11.	ANS:	E	PTS:	1	DIF:	L1	
OBJ:	35.6 Combining Resistors in a Compound Circuit	STA:	Ph.5.a | Ph.5.c
KEY:	resistance | unit		BLM:	knowledge

	12.	ANS:	A	PTS:	1

	13.	ANS:	A	PTS:	1	DIF:	L2	OBJ:	34.5 Ohm's Law
STA:	Ph.5.b	KEY:	ohm | current | voltage	BLM:	application

	14.	ANS:	A	PTS:	1	DIF:	L2	OBJ:	34.5 Ohm's Law
STA:	Ph.5.b	KEY:	power | bulb | resistance	BLM:	application

	15.	ANS:	B	PTS:	1	DIF:	L2	OBJ:	34.11 Electric Power
STA:	Ph.5.a | Ph.5.b | Ph.5.c	KEY:	outlet | current		
BLM:	application

	16.	ANS:	A	PTS:	1	DIF:	L2	OBJ:	35.4 Parallel Circuits
STA:	Ph.5.a	KEY:	parallel | circuit | lamp	BLM:	comprehension

	17.	ANS:	C	PTS:	1	DIF:	L2	OBJ:	35.4 Parallel Circuits
STA:	Ph.5.a	KEY:	parallel | bulb | circuit		BLM:	application

	18.	ANS:	B	PTS:	1	DIF:	L2	
OBJ:	35.6 Combining Resistors in a Compound Circuit	STA:	Ph.5.a | Ph.5.c
KEY:	resistor | series			BLM:	application

	19.	ANS:	D	PTS:	1	DIF:	L2	OBJ:	34.11 Electric Power
STA:	Ph.5.a | Ph.5.b | Ph.5.c	KEY:	bulb | outlet	BLM:	application

	20.	ANS:	C	PTS:	1	DIF:	L2	OBJ:	34.11 Electric Power
STA:	Ph.5.a | Ph.5.b | Ph.5.c	KEY:	bulb | volt | power	
BLM:	application

	21.	ANS:	B	PTS:	1	DIF:	L2	OBJ:	34.11 Electric Power
STA:	Ph.5.a | Ph.5.b | Ph.5.c	KEY:	power | resistance	
BLM:	application

	22.	ANS:	C	PTS:	1	DIF:	L2	OBJ:	37.1 Electromagnetic Induction
STA:	Ph.5.a	KEY:	induce | current		BLM:	comprehension

	23.	ANS:	B	PTS:	1	DIF:	L2	OBJ:	37.1 Electromagnetic Induction
STA:	Ph.5.a	KEY:	current | wire | magnet	BLM:	comprehension

	24.	ANS:	A	PTS:	1	DIF:	L2	OBJ:	37.1 Electromagnetic Induction
STA:	Ph.5.a	KEY:	magnet | coil | wire		BLM:	comprehension

	25.	ANS:	B	PTS:	1	DIF:	L2	OBJ:	37.1 Electromagnetic Induction
STA:	Ph.5.a	KEY:	magnet | coil | speed		BLM:	comprehension

	26.	ANS:	C	PTS:	1	DIF:	L2	OBJ:	37.5 Transformers
STA:	Ph.5.a | Ph.5.b			KEY:	transformer | voltage	
BLM:	comprehension	

	27.	ANS:	A	PTS:	1	DIF:	L2	OBJ:	37.5 Transformers
STA:	Ph.5.a | Ph.5.b			KEY:	coil | transformer	
BLM:	comprehension	

	28.	ANS:	B	PTS:	1	DIF:	L2	OBJ:	37.5 Transformers
STA:	Ph.5.a | Ph.5.b			KEY:	voltage | transformer	
BLM:	application

	29.	ANS:	B	PTS:	1	DIF:	L2	OBJ:	37.5 Transformers
STA:	Ph.5.a | Ph.5.b			KEY:	transformer | voltage	
BLM:	application

	30.	ANS:	A	PTS:	1	DIF:	L1	OBJ:	37.2 Faraday's Law
KEY:	faraday's law | induction | voltage	BLM:	knowledge

	31.	ANS:	C	PTS:	1

	32.	ANS:	B	PTS:	1

	33.	ANS:	D	PTS:	1

	34.	ANS:	B	PTS:	1

	35.	ANS:	B	PTS:	1

	36.	ANS:	A	PTS:	1

	37.	ANS:	A	PTS:	1

	38.	ANS:	D	PTS:	1

	39.	ANS:	C	PTS:	1

	40.	ANS:	D	PTS:	1