Download PHY 101 - Oakton Community College

PHY 101–002
Oakton Community College
Fall 2009
Practice Test 4
1) Two charged particles that are held close to each other are released. As they move, the force on each
other increases. Therefore, the particles have
A) the same sign
B) opposite signs
C) not enough information given
2) Two charged particles attract each other with a force F. If the charges of both particles are doubled, and
the distance between them also doubled, then the force of attraction will be
A) F
B) 2F
C) F/2
D) F/4
E) none of these
3) When a single charge q is place at the corner of a square, the electric field at the center of the square, due
to that charge, is F/q. If two other equal charges are placed at adjacent corners of the square, the electric
field at the center of the square, due to the three charges, is:
A) F/q
B) 4F/q
C) F/(2q)
D) F/(4q)
E) none of these
4) Electrical potential, measured in volts, is the ratio of electrical potential energy to the amount of
electrical
A) current
B) resistance
C) charge
D) voltage
E) none of these
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PHY 101–002
Oakton Community College
Fall 2009
Practice Test 4
5) Normally, a balloon charged to several thousand volts has a relatively small amount of
A) charge
B) energy
C) both
D) neither
6) Two charges separated by one meter exert 1 N forces on each other. If the charges are pushed to 1/4
meter separation, the force on each charge will be
A) 1 N
B) 2 N
C) 4 N
D) 8 N
E) 16 N
7) The current through a 10  resistor connected to a 120 V supply is
A) 1 A
B) 10 A
C) 12 A
D) 120 A
E) none of these
8) The electric power of a lamp that carries 2 A at 120 V is
A) 1/6 W
B) 2 W
C) 60 W
D) 20 W
E) 240 W
9) A 60 W bulb and a 100 W bulb are both rated at 120 V. which light bulb has a higher resistance?
A) the 60 W bulb
B) the 100 W bulb
C) they both have the same resistance
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PHY 101–002
Oakton Community College
Fall 2009
Practice Test 4
10) Two lamps, one with a thick filament, one with a thin filament of the same length, are connected in
series with a battery. The current is greater in the lamp with the:
A) thick filament
B) thin filament
C) same in each lamp
11) Two lamps, one with a thick filament, one with a thin filament of the same length, are connected in
parallel to a battery. The current is larger in the lamp with the:
A) thick filament
B) thin filament
C) same in each lamp
12) A 40 Ω resistor and a 60 Ω resistor are connected in series. What is the equivalent resistance?
A) 0.67 Ω
B) 1.5 Ω
C) 100 Ω
D) 24 Ω
13) A 40 Ω resistor and a 60 Ω resistor are connected in parallel. What is the equivalent resistance?
A) 100 Ω
B) 24 Ω
C) 0.04167 Ω
D) 0.01 Ω
14) Moving electric charges will interact with
A) an electric field
B) a magnetic field
C) both
D) neither
15) If a steady magnetic field exerts a force on a moving charge, that force is directed
A) in the opposite direction as the motion
B) in the direction of the motion
C) at right angles to the direction of the motion
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PHY 101–002
Oakton Community College
Fall 2009
Practice Test 4
16) Several paper clips dangle from the south pole of a magnet in a chain-like fashion. The induced pole at
the bottom of the lowest paper clip is
A) north pole
B) south pole
C) could be either
17) Magnetic field lines around a current-carrying wire
A) extend radially from the wire
B) go in circles around the wire
C) both of these
D) neither of these
18) A magnetic field exists in front of you that is directed from left to right. You shoot electrons straight
out in front of you into that field. The electrons are
A) not affected by the field
B) is deflected in the left-right direction
C) is deflected in the vertical direction
D) goes faster away from you
19) The force from which field can increase a moving electron’s speed?
A) electric field
B) magnetic field
C) both of these
D) neither of these
20) Can a constant magnetic field induce a voltage on a stationary loop of wire?
A) yes, always
B) no, the magnetic flux through the loop must change
C) it depends on the strength of the constant magnetic field
D) there is not enough information to tell
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PHY 101–002
Oakton Community College
Fall 2009
Practice Test 4
21) If there is a magnetic field going through a loop of wire, which of the following could cause a voltage
to be induced on the wire loop?
A) a change in the strength of the magnetic field
B) the size of the loop is changed so that the area inside it changes
C) the loop is turned so that the magnetic field goes through the loop at a different angle
D) all of the above
E) none of these
22) Which of these things happen if the current going through a solenoid is changed?
A) the magnetic field inside the solenoid changes
B) a back emf is produced that pushes against the current change
C) both of these
D) none of these
23) Which of the following can not be done using a transformer?
A) convert 120 V ac power to 9 V ac power
B) convert 9 V ac power to 120 V ac power
C) convert 10,000 V ac power to 120 V ac power
D) convert 120 V dc power to 9 V dc power
E) all of these can be done using a transformer
24) A transformer is used to convert a 120 V (ac) input into a 9 V (ac) output. Which of the following turns
ratios could be used for the transformer?
A) 30:40
B) 400:30
C) 120:90
D) 1600:9
E) none of these
25) For the circuit of problem 24, the current on the output side of the transformer is 40 mA (ac). What is
the (ac) current on the input side?
A) 3 mA (ac)
B) 533 mA (ac)
C) 27,000 A (ac)
D) 40 mA (ac)
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