VGMVG+Part+FyBCh20 21NVC07+Magnetism+and+Magnetic+Induction

8/3/2019 VGMVG+Part+FyBCh20 21NVC07+Magnetism+and+Magnetic+Induction

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VG/MVG part FyBCh20-21NVC07 Magnetism and Magnetic Induction NV-College

FyBCh20-21NVC07

VG/MVG-Level Test On Magnetism and Magnetic InductionInstructions:

The Test Warning! There are more than one version of the test.

Tools Approved formula sheets, ruler, and graphic calculator. You may use your personalized

formula booklet which has your name on it. This should be submitted along with the

test.

Time: 10:10-11:25; Friday Feb 12, 2010

The multi-choice problems must be answered on the this paper. The solutions to each

question must also be answered in the space provided. Only, if you need additional

space you may write your solutions in an additional page that will be provided if

needed.

Limits: There are 9 problems in this test and it gives at maximum 31 points, 17 of which areVG points. Problems number 8 and 9 are of the greatest important for MVG.

Pass (G): minimum 10 points

VG: G+ in the G test. minimum of total 21 points , 6 of which are VG points

MVG: G+ in the G test. minimum of total 24 points , 11 of which are VG points and MVG

quality in all problems specially on the problems 8 and 9.

Please answer as clear as possible. Do not forget the UNITS!

Enjoy it! Behzad

1 2 3 4 5a 5b 6A 6B 6C 7A 7B 8¤ 9¤ Sum 10 min G VG_Points

G 1 1 1 1 1 1 1 1 2 1 1 0 2 14 21 min VG 6

VG 2 1 1 1 1 1 0 0 0 1 1 4 4 17 24 min MVG 11

G Grade

VG

© [email protected] Not for Sale. Free to use for educational purposes. 1/4




1. High voltages are used in electric transmission line

a. to minimise the energy loss as power dissipated in the wires.

b. to minimise the cost. High voltage electricity is cheaper.

c. because electricity travels faster in high voltage.

d. To avoid electric shock.

Answer: Alternative ____________ [1/0]

Why? Explain! Give an example. [0/2]

2. The reactance of a capacitor is X when an AC voltage of frequency f is applied to it.

If the frequency is changed to2

f , the reactance becomes

a. 2

X

b. X 2

c. X

d. X 4 Answer: Alternative ____________ [1/0]

Why? Explain! [0/1]

3. Which of the following can operate only on alternating current ?

a. A transformerb. An electric motor

c. An electric lamp

d. None


Why? Explain! [0/1]





4. A wire loop is rotated at constant speed in a magnetic field.

a. The induced emf is constant.

b. The induced emf is 0.

c. The induced emf varies between 0 and ( )maxemf .

d. The induced emf varies between ( )maxemf − and ( )maxemf .


Why? Explain! [0/1]

5. A resistor, a capacitor, an an inductor are connected to an AC power source of

frequency f . The effective voltages across the circuit components are V V ,

V , and V V .

R 0.10=

V C 0.20= L 0.14=

a. Find the effective voltage of the source. [1/1]

b. Find the phase angle in the circuit. [1/1]

6. The figure below is an oscilloscope connected to AC voltage.

a) Find the maximum voltage. [1/0]

b) Find the effective value of the voltage. [1/0]c) Find the frequency of the AC source. [2/0]

2.0 V

5 ms

7. If MW 75 of power at kV 55 arrives at a town from a generator via Ω0.5 transmission lines, calculate

a. the emf at the generator end of the lines, [1/1]

b. the fraction of the power generated that is lost in the lines. [1/1]






In assessing your work with the following problems 8 AND 9 your teacher willpay extra attentio to:

∗ How well you plan and carry out the task.

∗ Which priciples of physics you use and how you justify using them

∗ How general your solutions are∗ How well you justify your conclusions

∗ How well you cary out your calculations

∗ How well you present your work

∗ How well you use physical and matematical language.

∗ How clear your solutions are.

8. An circuit illustrated in the figure below has an inductance of mH 00. and a

capacitance of pF 0. . Thecapacitor is charged with a V

battery. The capacitor is then

connected to the inductor. [0/4/¤]

LC − 5

200.50

a. Find the natural frequency of

the circuit.

b. Find the maximum charge on

the capacitor.

c. Find the maximum current in

the circuit.

d. Find the charge on thecapacitor as a function of time.

e. Find the current in the circuit as a function of time.

9. A conducting loop of total resistance Ω00.4 is partially placed in a uniform magnetic

field whose magnitude increases as function of time according to200.600.300.2 t t B ⋅+⋅+=

Where B is in Tesla and t is the time in second. As illustrated in the figure below, the

loop consists of four 50 metal bars and longer metal bar of size . The

metal bars are connected to each other such

that only the part that makes a triangle shape

is in the magnetic field region. [2/4/¤]

cm0.

ime.

ate the magnitude and direction of

e on of

cm0.80

a. Calculate the magnitude and direction of

the induced current as a function of t

b. Calcul

the induced current at st 00.5= .

c. Calculate the magnitud and directi

the induced current if the magnetic field

is drops to zero at st 00.5= in

s200.0

cm0.50

cm0.80

200.600.300.2 t t B ⋅+⋅+=

pF 0.20

mH 00.5

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VGMVG+Part+FyBCh20 21NVC07+Magnetism+and+Magnetic+Induction