Quiz Electronics Engineering 17 Aug 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 17/08/2020

Each Question carries 1 Mark
Negative Marking: 1/4
Time: 10 Minutes

Q1. The transconductance is measured in
(a) volts
(b) amperes
(c) ohms
(d) mhos.

Q2. Frequency shift keying is used mostly in:
(a) Telegraphy
(b) Telephony
(c) Satellite communication
(d) Radio transmission

Q3.The Biot Savart’s law is a general modification of
(a) Coulomb’s law
(b) Ampere’s law
(c) Faraday’s law
(d) Ohm’s law

Q4. Intel 8085 is a ________ microprocessor.
(a) 8-bit CMOS
(b) 16-bit NMOS
(c) 8-bit NMOS
(d) 16-bit CMOS

Q5. Consider an ideal low pass filter. Such a discrete time system is
(a) always realizable
(b) never realizable physically
(c) a non-linear system
(d) a linear, causal system

Q6. The noise is more dominant in which of the following:
(a) PAM
(b) PWM
(c) PPM
(d) FSK

Q7. The complement accumulator(CMA) instruction of 8085 processor in execution affects –
(a) Zero Flag
(b) Sign Flag
(c) Carry Flag
(d) None of the above

Q8. The material used for fuse must have
(a) low melting point and low specific resistance
(b) high melting point and low specific resistance
(c) Low melting point and high specific resistance
(d) None of these

Q9. The Boolean function (x + y)(x ̅+z)(y+z) is equal to which one of the following expressions?
(a) (x+y)(y+z)
(b) (x ̅+z)(y+z)
(c) (x+y)(x ̅+z)
(d) (x+y)(x+z ̅)

Q10. Which of the following is not a non-linear element?
(a) Tunnel diode
(b) Heater coil
(c) Gas diode
(d) Electric arc.

SOLUTIONS

S1. Ans.(d)
Sol. The transconductance is the ratio of the change in current at the output terminal to the change in the voltage at the input terminal of an active device.

S2. Ans. (a)
Sol. Frequency-shift keying (FSK) allows digital information to be transmitted by changes or shifts in the frequency of an analog carrier signal. This binary data is converted by a modem into an FSK signal. This will be transmitted via telephone lines, fiber optics or wireless media.
In Frequency Shift Keying system, narrow bandwidth is used so it is an efficient system used in modulation system for telegraphy.

S3. Ans.(b)
Sol. The Biot Savart’s law is also called Ampere’s law.

S4. Ans.(c)
Sol. Features of 8085 microprocessor is –
• 8-bits
• NMOS technology
• 40 pins dual-in line package
• clock frequency is 3 MHz.
• clock cycle is 300 ns.
• 74 basic instructions and 246 opcodes

S5. Ans.(b)
Sol. Inverse Fourier Transform of rectangular pulse frequency response of low pass filter is a sinc function. This is not ‘0’ for t < 0. Therefore, system cannot be realized physically.

S6. Ans.(a)
Sol. Noise is more dominant in PAM because noise affects the amplitude of the message signal most.

S7. Ans.(d)
Sol. None of the flags are affected due to the application of CMA instruction.

S8. Ans.(c)
Sol. Fuse wire is made-up of highly resistive material in order to carry the heavy fault current for a short time. So, it has high specific resistivity. Fuse wire must melt itself in fault condition in order to break the circuit so it must have low melting point.

S9. Ans.(c)
Sol.
(x+y)(x ̅+z)(y+z)
=(xx ̅+ xz+x ̅y+yz)(y+z)
=(xz+x ̅y+yz)(y+z) [∵ xx ̅ = 0]
=xyz+xzz+x ̅yy+x ̅yz+yyz+yzz
=xyz+xz+x ̅y+x ̅yz+yz+yz [∵ zz = z]
=xz( y+1)+x ̅y(1 + yz) + yz
= xz + x ̅y + yz
=xx ̅+xz+x ̅y+yz
=x(x ̅+z)+y(x ̅+z)
=(x+y)(x ̅+z)

S10. Ans (b)
Sol. The non-linear element is an electronic component and the parameters of this component differ with respect to the current and the voltage. The other parameters like waveforms, resistance, inductance may not be constant in Non- linear element.

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