HOUSTON COMMUNITY COLLEGE
PHYS 2326:
UNIVERSITY PHYSICS-II
Instructor: Dr. Khalid Bukhari
Exam-III:
.
Name: ________________________________________
Chapters: 28, 29, 30, 31, 32, 33
Q1
Q1a)
(10 + 10 marks)
A step-down transformer is to be made for a cell phone charger. The household voltage
(primary side) is 120 V (rms), and the voltage required on the secondary side (cell-phone
side) is 4 V (rms). The power needed on the secondary side is 6 watts.
i) If the number of turns on the primary side is 120, how many turns should be on the
secondary side.
ii) What will be the (rms) currents in the primary and secondary sides.
Q1b)
Find the current in the 3 Ω resistor in the following circuit.
3Ω
5Ω
I2
I1
6Ω
I4
I3
2Ω
5V
Q2
(20 marks)
Solve the following circuit for the currents I 1, I2 and I3. In your result, clearly
indicate the directions of the three currents.
3Ω
5Ω
I2
I1
6Ω
5V
10 V
I3
Q3
Q3a)
(10 + 10 marks)
Determine the initial direction of the
deflection of the charged particles as
they enter the magnetic fields shown in
the Figure. Give your answer in terms of ‘to
left’, ‘to right’, ‘upward’, downward’, ‘in
to page’, out of page’, ‘no deflection’.
Q3b
In a particle accelerator, a proton moving at a speed of 6 x 10 6 m/s has to be maintained in
a circular path of radius 3 meters. What should be the strength of the magnetic field to
achieve this?
Q4a
Q4a)
(10 + 10 marks)
A research lab has a long length of wire carrying a large DC current of 100 A. How far away
from this wire will the magnetic field be 0.01 T.
Q4b)
An RLC circuit consists of a 200-  resistor, a 20.0-F capacitor, and a 400-mH inductor
connected in series with a 120-V, 60.0-Hz power supply. What is the phase angle between
the current and the applied voltage?
Q5
(10 + 10 marks)
A toroidal magnetic field of strength 5.0 Tesla is required in a torus of
inner radius 1.0 m and outer radius 1.5 m. The number of turns of wire is 2000.
Calculate the current that must pass through the wire to produce the required magnetic
field.
If the wire is made of copper and is of diameter 0.5 cm, what will be the total power loss
due to resistive heating in the wire. The length of the wire may be assumed to be 3000 m.
The electrical resistivity of copper is …….
Q5a)
Q5b)
Q6
Q6a)
(8 + 6 + 6 marks)
To produce electricity by using the earth’s magnetic field, you make a coil of 1 meter
diameter having 50 turns. It is placed where the Earths’ magnetic field is 50 Gauss. This coil is
then rotated so that it turns by 180° in 0.1 second. What average emf would be generated
in the coil? 1 Gauss = 0.0001 Tesla
Q6b)
An RL circuit is to be made that have time constant of 2 s. If the resistance to use is 2,000 Ω,
what value of the inductance is needed.
A 4.0-μH inductor is connected in series with a variable capacitor in the tuning section of a
short wave radio set. What capacitance tunes the circuit to the signal from a radio
transmitter broadcasting at 4.50 MHz?
Q6c)