Electronics Engineering - Online Test
Q1. 
In the figure shown below, the chopper feeds a resistive load from a battery source. MOSFET Q is switched at 250 kHz, with a duty ratio of 0.4. All elements of the circuit are assumed to be ideal
The average source current in Amps in steady-state is
Answer : Option B
Explaination / Solution:
No Explaination.
Q2. A 10 kHz even-symmetric square wave is passed through a bandpass filter with centre frequency at 30 kHz and 3 dB passband of 6 kHz. The filter output is
Answer : Option C
Explaination / Solution:
10 KHz even symmetric square wave have frequency component present 10KHz, 30KHz, 50KHz, 70KHz
[only odd harmonics due to half wave symmetry]
Since bandpass filter is contered at 30KHz, 30KHz component will pass through
filter output is nearly perfect cosine wave at 10 KHz
Cosine in due to reason that signal in even signal.
Q3. A 3-phase balanced load which has a power factor of 0.707 is connected to balanced supply. The power consumed by the load is 5kW. The power is measured by the two wattmeter method. The readings of the two wattmeters are
Answer : Option A
Explaination / Solution:
satisfiying only for(A)
Q4. A λ/2 dipole is kept horizontally at a height of λ0/2 above a perfectly conducting
infinite ground plane. The radiation pattern in the lane of the dipole (
plane)
looks approximately as
plane)
looks approximately as
Answer : Option B
Explaination / Solution:
Q5. A single-phase, 22 kVA, 2200 V/ 220 V, 50 Hz, distribution transformer is to be connected as an auto-transformer to get an output voltage of 2420 V. Its maximum kVA rating as an autotransformer is
Answer : Option C
Explaination / Solution:
Q6. A silicon wafer has 100 nm of oxide on it and is furnace at a temperature above
10000 C for further oxidation in dry oxygen. The oxidation rate
Answer : Option D
Explaination / Solution:
No Explaination.
Q7. The average power delivered to an impedance (4 - j3)Ω by a current 5cos(100πt +100) A is
Answer : Option B
Explaination / Solution:
Q8. A solid iron cylinder is placed in a region containing a uniform magnetic field such that the cylinder axis is parallel to the magnetic field direction. The magnetic field lines inside the cylinder will
Answer : Option A
Explaination / Solution:
Flux always chooses less reluctance path. So flux tried to flow inside the conductor and closer to the axis of the cylinder.
Q9. The Bode plot of a transfer function G(s) is shown in the figure below.
The gain (20 log |G(s)|) is 32 dB and -8 dB at 1 radians/s and 10 radians/s
respectively. The phase is negative for all ω.Then G(s) is
Answer : Option B
Explaination / Solution:
No Explaination.
Q10. A continuous random variable X has a probability density function 
is
is
Answer : Option A
Explaination / Solution:
No Explaination.
