Name: ________________________ Class: ___________________ Date: __________
ID: A
Exam 4--PHYS 202--Spring 2016
Multiple Choice (20 pts)
Identify the choice that best completes the statement or answers the question.
1. A current travels through a wire as shown. What is
the direction of the force on the wire?
a.
b.
c.
d.
e.
3. Consider this loop of wire. What will happen to
the coil as time continues?
down
to the right
to the left
up
into the page
a.
b.
c.
2. Magnetic field lines inside the solenoid shown are:
d.
a.
c.
d.
clockwise circles as one looks down the axis
from the top of the page
counterclockwise circles as one looks down the
axis from the top of the page
toward the top of the page
toward the bottom of the page
e.
in no direction since B = 0
b.
it will come to a complete stop after 1 rotation.
it will turn but gradually slow down as it loses
energy
it will turn clockwise for 1/2 turn and then
counterclockwise for 1/2 turn, oscillating back
and forth
it will continue to turn in the same direction
until the current is turned off
4. Consider this function. In which quadrant would
you draw the phasor to represent the function at the
location of the dotted line?
a.
b.
c.
d.
1
I
II
III
IV
Name: ________________________
ID: A
8. An inductor is ______.
a. a resistive, ohmic device
b. a solid state device
c. a coil of wire
d. a type of capacitor
5. A current-carrying wire is moved towards a
conducting loop in the direction shown. As the wire
is moving, is there a cw current around the loop, a
ccw current or no current?
9. The point A is equidistance between these two,
long parallel wires. What is the direction of the
magnetic field at point A due to the two wires?
a.
b.
c.
No current
Clockwise
Counterclockwise
6. Faraday’s law says the induced EMF is caused by
the _______________.
a. changing magnetic flux
b. constant electric field
c. moving charges
d. resistance in the circuit
a.
b.
c.
d.
e.
7. A square loop of copper wire is pulled through a
region of magnetic field. Rank in order, from
strongest to weakest, the pulling forcesthat must be
applied to keep the loop moving at constant speed.
a.
b.
c.
d.
e.
Into the page
Out of the page
To the right
To the left
There is no magnetic field at A
10. What type of transformer is on the utility pole
outside of your house?
a. upside-down transformer
b. step-up transformer
c. DC transformer
d. step-down transformer
F3 > F2 = F4 > F1
F2 = F4 > F1 = F3
F4 > F3 > F2 > F1
F4 > F2 > F1 = F3
F3 > F4 > F2 > F1
2
Name: ________________________
ID: A
Problem
12. (5 pts) A positive particle moves into the B-field of
a mass spectrometer; the particle is moving at a
speed of 2 m/s. The magnetic field has a
magnitude of 2.0 T, and the radius of the particle’s
path is 0.5 m. Following is a table with the masses
and charges of some imaginary particles. Which is
this particular particle?
11. (10 pts) Consider this circuit. A portion of the
circuit sits in a constant magnetic field. What is
the magnitude and direction of the force on the
segment of wire. The wire has a length of 0.5 m.
.
13. (5 pts) Consider this transformer; the primary coil
has 4 turns, and the secondary coil has 8 turns of
wire. The primary voltage is 100 V of AC
electricity that oscillates at a rate of 60 Hz.
a) What is the secondary voltage?
b) Is this a step-up or step-down transformer?
c) At what frequency does the secondary voltage
oscillate?
.
3
Name: ________________________
ID: A
14. (15pts) Consider this circuit. The circuit has just been assembled and current has begun to flow.
a. What is the equilibrium current?
b. How long does it take to reach that current?
c. How long does it take to reach one-half of this equilibrium
current?
d. When it is at this current, what is the energy stored by the
inductor?
e. Sketch the I vs t (current vs time) graph for this circuit.
.
4
Name: ________________________
ID: A
15. (15 pts) A single loop circuit has a 10.0 Ω resistor, 5.0 H inductor, and a 3.0 µF
capacitor. Initially, the capacitor has 6.0 µC, and the current is zero. (For this question only, your calculator
should be in radian mode!)
a) What is the charge on the capacitor at t=0.1 s?
b) When is the first time the change on the capacitor is zero?
c) Sketch a graph of current vs time for this circuit.
5
Name: ________________________
ID: A
16. (15 pts) In this figure, the magnetic field through the loop changes according to this function: B=6.0t+5t 2, where
B is in tesla and t is in seconds. The area of the loop is 0.01 m 2. The wire has a resistance of 3.0 Ω.
a) What is the magnetic flux at t=2.0 s?
b) What is the magnitude of the EMF induced at t=2.0 s?
c) What is the magnitude and direction of the current in the loop?
.
6
ID: A
Exam 4--PHYS 202--Spring 2016
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
C
C
C
C
B
A
B
C
B
D
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
1
1
1
1
1
1
1
1
1
1
PROBLEM
11. ANS:
.
PTS: 1
12. ANS:
Delirium
PTS: 1
13. ANS:
.
PTS: 1
14. ANS:
.
PTS: 1
15. ANS:
.
PTS: 1
16. ANS:
.
PTS: 1
1