Electronics Engineering - Online Test
Q1. The current state QAQB of a two JK flip-flop system is 00. Assume that the clock rise-time is much
smaller than the delay of the JK flip-flop. The next state of the system is
Answer : Option C
Explaination / Solution:
Q2. In the Digital-to-Analog converter circuit shown in the figure below, VR = 1V and R = 1kΩ
The voltage V is
Answer : Option C
Explaination / Solution:
No Explaination.
Q3. Let ⊕ denote the Exclusive OR (XOR) operation. Let ‘1’ and ‘0’ denote the binary
constants. Consider the following Boolean expression for F over two variables P and Q.
F(P,Q) = ((1⊕P)⊕(P⊕Q))⊕((P⊕Q)⊕(Q⊕0))
The equivalent expression for F is
Answer : Option D
Explaination / Solution:
Q4. The circuit shown in the figure is used to charge the capacitor C alternately
from two current sources as indicated. The switches S1 and S2 are mechanically
coupled and connected as follows:
Assume that the capacitor has zero initial charge. Given that u(t) is a unit step function , the voltage vc(t) across the capacitor is given by
Answer : Option C
Explaination / Solution:
Q5. For the power semiconductor devices IGBT, MOSFET, Diode and Thyristor, which one of the following statements is TRUE?
Answer : Option D
Explaination / Solution:
MOSFET → Majority carrier device (NMOS, PMOS)
Diode → both majority & minority carrier device
Transister → Npn, pnp
IGBT → input is MOSFET, Output is BJT
Q6. Silicon is doped with boron to a concentration of 4 × 1017 atoms cm3. Assume
the intrinsic carrier concentration of silicon to be 1.5 × 1010/cm3 and the value
of kT/q to be 25 mV at 300 K. Compared to undopped silicon, the fermi level
of doped silicon
Answer : Option C
Explaination / Solution:
Q7. A uniform plane wave in the free space is normally incident on an infinitely thick dielectric slab (dielectric constant ε = 9). The magnitude of the reflection coefficient is
Answer : Option C
Explaination / Solution:
Q8. Two magnetically uncoupled inductive coils have Q factors q1 and q2 at the
chosen operating frequency. Their respective resistances are R1 and R2 . When
connected in series, their effective Q factor at the same operating frequency is
Answer : Option C
Explaination / Solution:
No Explaination.
Q9. The pressure coil of a dynamometer type wattmeter is
Answer : Option B
Explaination / Solution:
Since all the applied voltage appears across it.
Q10. Consider an LTI system with transfer function
If the input to the system is cos(3t) and the steady state output is Asin (3t + α), then the value of A is
Answer : Option B
Explaination / Solution:
