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Q-1
To keep a ball of mass m moving in a circle of radius r at constant
speed u requires a force on the ball that is
A) Directed toward the center of the circle and equal to mv2/r
B) Directed toward the center of the circle and equal to 5mv2/2r
C) Directed away from the center of the circle and equal to mv2/r
D) Directed away from the center of the circle and equal to mv2/2r
Q-2 Three charges, q, 2q, and 2q are located at the vertices of an
equilateral triangle as shown. A fourth charge q of mass 1 gram is
placed at the center of the triangle. What should q be for m to be
suspended at the center? |
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A) It is impossible for m to be suspended at center for any value of q
B) 0.5 ?c
C) 3.30 µC
D) 0.6 µC
E) 1.04 µC
Q-3 F1 is the electric flux through the disk of radius a. F2 is the
electric flux through the spherical surface of radius 3a containing a
hole of radius a
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A) F1 > F2
B) F1 < F2
C) F1 = F2
D) F1 = 0.5 F2
Q-4 A circuit consisting of three different capacitors is connected to
a battery, as shown in the figure.
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Calculate the equivalent capacitance for this circuit.
A) Ceq = 1.56 ?f
B) Ceq = 1.71 ?f
C) Ceq = 3.71 ?f
D) Ceq = 5.20 ?f
E) Ceq = 9 µF
Q-5 A 10 V battery with an internal resistance of 2 O provides power to
a resistor network as shown in the figure.
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How much current does the battery supply?
A) IB = 0.15 A
B) IB = 0.32 A
C) IB = 0.47 A
D) IB = 0.68 A
E) IB = 0.80 A
Q-6 An electromagnetic plane wave is propagating in the vacuum. The
electric field at time t = 0 over two wavelengths is sketched in the
figure below. The E-field is given by E(x,y,z,t) = i Eo sin(kz + ?t).
Here, i is the unit vector in the +x direction, j is the unit vector in
the +y direction, and k is the unit vector in the +z direction.
In which direction does the wave propagate?
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A) It propagates in the +z direction
B) It propagates in the -z direction.
C) It propagates in the -x direction.
D) It propagates in the +y direction.
Q-7 Which of the following materials is not a semiconductor?
A) Gallium nitride
B) Germanium
C) Gallium
D) Silicone
Q-8
What would be a typical magnitude for the reverse current in a
general-purpose silicon diode?
A) A few picoamps.
B) A few nanoamps
C) A few microamps.
D) A few milliamps.
Q-9 Which of the following statements is incorrect?
A) At room temperatures, pure semiconductors make excellent conductors
B) Conduction within pure semiconductors is termed intrinsic conduction.
C) Doping pure semiconductor material with small amounts of donar
impurities produces an p-type & n-type semiconductor.
D) The dominant charge carriers within a doped semiconductor are called
majority charge carriers
Q-10 Estimate the bandwidth of a signal with the following frequency
spectrum.
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A) 700 Hz.
B) 200 Hz.
C) 1200 Hz.
D) 500 Hz
Q-11
What is the effect of negative feedback on the gain of an amplifier?
A) It reduces the gain by a factor of (1 + AB).
B) It increases the gain by a factor of (1 + 2AB).
C) It reduces the gain by a factor of 1/2B.
D) It increases the gain by a factor of 1/B.
Q-12 Which of the following statements is incorrect?
A) In circuits using n-channel FETs the supply voltage is normally more
positive than the source.
B) The operation of FETs is essentially non-linear
C) All FETs have very high input resistance.
D) The transconductance of a FET is given by gm = ID/VGS.
Q-13
What are the characteristics of the following circuit? |
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A) A high voltage gain, a high output resistance and a low output resistance
B) A voltage gain of 1, a high input resistance and a low output
resistance
C) A high voltage gain of .5, a low input resistance and a high output
resistance.
D) A voltage gain of 1, a low input resistance and a high output
resistance
Q-14
A continuous time signal Xc(t) is sampled at sampling frequency
fs=1/T=5Hz to obtain a discrete-time signal x[n]=xc(nT). Which of the
continuous time sinusoids in Figure 8(a) could be sampled at this rate
without aliasing? |
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A) Xc(t)
B) Xb(t)
C) Xc(t)
D) Xd(t)
E) Xe(t)
F) None of the above
Q-15 the following abbreviations are used : FT= Fourier Transform, FS=
Fourier series, DT= Discrete - time, and CT= Continious – Time, DFT=
Discrete Fourier Transform, FFT= Fast fourier Transform. Assume the
signal is Real-Value, then what transform is actually calculated by
hardware, such as digital oscilloscopes to estimate the CTFT ?
A) CTFT
B) CTFS
C) DTFS
D) DTFT
E) DFT
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