ame: ________________________
Exam 2--PHYS 102--S10
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. Which of these equations correctly describes this circuit?
a.
b.
____
80I 3 + 1I 3 + 30 + 45I 1 = 0
−80I 3 − 1I 3 − 30 − 20I 2 − 40 = 0
c.
d.
I1 + I2 = I3
45I 1 + 20I 2 − 40 = 0
2. Which of these statements about a household circuit is true:
I. The household circuit is a parallel circuit.
II. All devices in a household circuit operate at the same current.
III. As you add more devices to a household circuit, the potential across each device
IV. The circuit breaker turns off if I in>Iout for any particular device.
a.
b.
I & IV
I
c.
d.
1
II & III
I & II
decreases.
____
3. In this circuit, how much brighter or dimmer is bulb A compared with bulb C? Assume the bulbs have the
same resistance.
A
C
B
10 V
____
a. A is twice as bright as C
d. A is 1/4 as bright as C
b. A is 1/2 as bright as C
e. A has the same brightness as C
c. A is 4 times as bright as C
4. In this circuit, what happens to the equivalent resistance as you add resistors in parallel?
a.
b.
equivalent resistance increases
equivalent resistance stays the same
c.
d.
2
equivalent resistance decreases
It depends on the value of the added
resistance
____
5. A wire carries a current and sits in a magnetic field as shown. What is the direction of the force on the wire?
____
a. out of the page
d. left
b. down
e. into the page
c. up
6. What is the initial direction of this positively charged particle when it enters the magnetic field as shown?
____
a. left
d. up
b. into the page
e. right
c. out of the page
7. This figure shows the path of a charged particle. What is the charge of the particle?
a.
b.
negative
positive
c.
d.
3
neutral
not enough information
____
____
8. Which pole of a magnet points towards the
magnetic north pole?
a. depends on where you are on the Earth
c. South
b. North
d. none of these
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. To the left
d. To the right
b. Out of the page
e. There is no magnetic field at A
c. Into the page
____ 10. Which of these forms of radiation in the electromagnetic spectrum has the highest energy?
a.
b.
radio
ultraviolet
c.
d.
4
microwaves
infrared
____ 11. Which of these relationships correctly describes the indices of refraction depicted in this figure?
a. n1=n2
c. n1<n2
b. n1>n2
d. Not enough information
____ 12. What physical property of glass allows for the creation of light-dispersing prisms?
a.
light travels slower in glass than air
c.
the dependence of the index of refraction
on wavelength
b. the triangular shape of prisms
d. the index of refraction for glass is higher
than that of air
____ 13. Which of these phenomena suggest that light acts as a particle?
I. Interference
II. Reflection
III. Refraction
IV. Photoelectric Effect
a.
b.
II & III
II & IV
c.
d.
5
IV
I & IV
____ 14. This figure shows a person looking at a star in a box filled with water. The actual position of the star is as
shown. Where does the person see the image of the star?
a.
b.
the image is at the same position as the
object
to the left of the actual star
c.
to the right of the actual star
d.
the person does not see an image
6
Problem
15. (15 pts) A 10 Ω and a 20 Ω resistor are in parallel, and the pair is in series with a 30 Ω resistor. The resistors
are hooked up to a battery with a voltage of 45 V. What is the potential across the 10 Ω resistor?
.
7
16. (15 pts) A particle carrying a -10 C charge moves with velocity v = 2j + 3k m/s
through a
uniform magnetic field B = 6i + 8j T. What is the force, in vector notation, on the charged
particle?
.
8
17. (10 pts) A wire of negligible resistance is bent into a rectangle as in this figure, and a battery and
resistor are connected as shown. The right-hand side of the circuit extends into a region containing a
uniform magnetic field of 2 T pointing into the page. Find the magnitude and direction of the net
force on the circuit.
.
9
18. (15 pts) Trace the path of this ray through the glass prism; the angles should be drawn in proper
proportionality. Calculate the angle of refraction when the light emerges from the glass. (The index of
refraction for glass is 1.5).
10
19. (15 pts) In this figure, a boy shines a flashlight so he illuminates his keys at the bottom of the lake. What is
the distance from the pier to the keys (x)? (The index of refraction for water is 1.3.)
.
11
20. Extra Credit (3 pts)
Use the matrix method to solve this system of equations:
x + 2y = 5
x + 3y = 7
2x + 4y + z = 13
.
12
ID: A
Exam 2--PHYS 102--S10
Answer Section
MULTIPLE CHOICE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
B
B
C
C
C
B
A
C
B
B
B
C
B
C
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
1
1
1
1
1
1
1
1
1
1
1
1
1
1
PROBLEM
15. ANS:
.
PTS: 1
16. ANS:
.
PTS: 1
17. ANS:
.
PTS: 1
18. ANS:
,
PTS: 1
19. ANS:
.
PTS: 1
20. ANS:
.
PTS: 1
1