Quiz Electronics Engineering 6 Oct 2020

Quiz Electronics Engineering
Exam: NIC
Topic: Miscellaneous
Date: 06/10/2020

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

Q1. If a circuit is at resonance, the applied voltage and resulting current are
(a) in phase
(b) out of phase by 90°
(c) out of phase by 270°
(d) out of phase by 180°

Q2. Maximum value of charging resistance in an UJT is associated with
(a) valley point
(b) peak point
(c) any point between peak and valley
(d) after the valley point

Q3. In a charge-free space, the Poisson equation results in which one of the following?
(a) Continuity equation
(b) Maxwell equation
(c) Laplace equation
(d) None of the above

Q4. Pretty good privacy (PGP) is used in ______
(a) Browser security
(b) Wi-Fi security
(c) FTP security
(d) Email security

Q5. Consider the following statements related to Fourier Series of a periodic waveform:
1. It expresses the given periodic waveform as a combination of DC component, sine and cosine waveforms of different harmonic frequencies.
2. The amplitude of spectrum is discrete.
3. The evaluation of fourier coefficients gets simplified if waveform symmetries are used.
4. The amplitude spectrum is continuous.
Which of the above statements are correct?
(a) 1, 2 and 3
(b) 2, 3 and 4
(c) 1, 3 and 4
(d) 1, 2 and 4

Q6. The device that generates the basic timing clock signal for the operation of the circuit using crystal oscillator is
(a) timing unit
(b) timing and control unit
(c) oscillator
(d) clock generator

Q7. In a low level AM transmitter, amplifier following the modulated stage must be
(a) class C amplifier
(b) linear devices
(c) non-linear devices
(d) harmonic devices

Q8. Secure shell network protocol is used for _________
(a) secure data communication
(b) remote command-line login
(c) remote command execution
(d) all of the above

Q9. Stack works on the principle of
(a) Last In First Out
(b) First In First Out
(c) Last In Last Out
(d) Random In Random Out

Q10. At resonant frequency a R-L-C series circuit draws maximum current due to the reason that
(a) the impedance is more than the resistance
(b) The difference between capacitance reactance and inductance reactance is zero.
(c) the voltage across the capacitor equals the applied voltage
(d) The power factor is less than unity

SOLUTIONS

S1. Ans.(a)
Sol. Since the current in the inductor and capacitor are 180 degrees out of phase of each other, the only current that flows in and out of the circuit is that of the resistor. In series circuits, current is the same through all components. At resonance, voltage across the resistor is in phase with the applied current.

S2. Ans.(b)

S3. Ans.(c)
Sol. Laplace Equation is
∇^2V = 0
Poisson Equation is
∇^2V = -ρ_v/ε
In charge free space region, ρ_v = 0
So, ∇^2V = 0
This is similar to Laplace equation.

S4. Ans.(d)
Sol. PGP is a data encryption computer program used in e-mail security to encrypt and decrypt texts, emails, and files which are to be transmitted over the internet to increase the security of emails.

S5. Ans.(a)

S6. Ans.(c)
Sol. The oscillator circuit generates the basic timing clock signal for the operation of the circuit using crystal oscillator.

S7. Ans.(b)
Sol. In a Low Level AM modulator the modulation is applied to low power stage of the transmitter. It is done in the RF generation stages, or via the digital signal processing areas. Linear amplification is required for the RF stages.

S8. Ans.(d)
Sol. SSH stands for Secure Shell. It is a cryptographic network protocol, used to access remote machine in order to execute command-line network services and other commands over a network. It is Known for its high security, cryptographic behavior and it is most widely used by network admins to control remote web servers primarily.

S9. Ans.(a)
Sol. In Stack, the data which is stored at last is at first moved out. So, the principle is called Last In First Out(LIFO).

S10. Ans.(b)
Sol. At resonance, impedance is minimum due to imaginary term of impedance Z is zero i.e. capacitive reactance is equal to inductive reactance. As impedance minimum so current flowing through a RLC circuit is maximum.