This preview shows pages 1–3. Sign up to view the full content.
Name: ________________________
Class: ___________________
Date: __________
ID: A
1
Final Exam
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
Constants
k
o
= 9.0x10
9
N m
2
/C
2
,
µ
o
= 4
π
x10
7
T m/A ,
ε
o
= 8.8x10
12
C
2
/Nm
2
, g =9.8 m/s
2
L
f
(water) = 334 kJ/kg, c(water) =4.2 kJ/kg
____
1.
The impedance of a 120
Ω
resistor, a 33
µ
F capacitor, and an 80 mH inductor in series and connected across
a 115 V ac wall outlet is:
a.
60
Ω
b.
80
Ω
c.
120
Ω
d.
130
Ω
e.
None of the above
____
2.
In an LRC circuit used for tuning the 95.3 MHz FM radio station the value of the resistor is 2.8
Ω
and the
inductor has a value of 1.6
H. The value of the capacitor in the circuit is:
a.
1.7 pF
b.
2.4 pF
c.
4.2 pF
d.
6.1 pF
e.
None of the above
____
3.
A series circuit with
R
= 96
Ω
,
L
= 16 mH, and
C
= 4.0
F is connected to a 12 V (peak value) AC source
with variable frequency. What is the rms current in the circuit at the resonance frequency?
a.
63 mA
b.
88 mA
c.
0.28 A
d.
0.35 A
e.
None of the above
____
4.
A sinusoidal current flows through an LC circuit at the resonance frequency.
When the current is zero the
absolute value of the voltage across the capacitor is __________ and the energy in the circuit is stored in the
_____________ field.
a.
maximum, magnetic
b.
maximum, electric
c.
zero, magnetic
d.
zero, electric
e.
none of the above
____
5.
In a transformer the number of turns in the primary is 200 and the number of turns in the secondary is 20.
An
ac voltage of 120 volts and 1.0 amps is applied to the primary.
The output from the secondary is ____ volts
and ______ amps. (ignore losses).
a.
20, 6
b.
6, 20
c.
12,10
d.
12, 1
e.
none of the above
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
ID: A
2
____
6.
An engine has a maximum theoretical efficiency of 36%. The temperature difference between the input and
the output is 432ºC. The temperature of the exhaust is:
a.
840º K
b.
768º K
c.
645º K
d.
447º K
e.
None of the above
____
7.
Two charges of +5.0
µ
C each are placed on two corners of an equilateral triangle of side 0.50 m. The
magnitude of the electric field at the third corner is:
a.
3.9
×
10
3
N/C
b.
2.8
×
10
4
N/C
c.
1.6
×
10
5
N/C
d.
zero
e.
None of the above
____
8.
Two capacitors of 80
F and 40
F are separately charged to 200
C and 80
C
,
respectively. They are
then connected in parallel so that the + plate of one goes to the  plate of the other
,
and vise versa. The final
voltage across the two capacitors is:
a.
0.80 V
b.
1.0 V
c.
1.4 V
d.
3.2 V
e.
None of the above
____
9.
A 1500 W room heater is used for 12 hours. At $0.085 per kilowatthour, the cost of operating the heater is:
a.
$3.24
b.
$2.35
c.
$1.53
d.
$1.12
e.
None of the above
____
10.
Two resistors, 6.0
Ω
and 9.0
Ω
connected in parallel, are in series with another combination of two resistors,
8.0
d.
9.3 W
e.
None of the above
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 01/24/2010 for the course PHYS 1 taught by Professor Onuich during the Spring '07 term at CSU Northridge.
 Spring '07
 Onuich
 Magnetism

Click to edit the document details