Electronic Science - Online Test
Q1.
magnetic intensity is defined by
Answer : Option B
Explaination / Solution:
No Explaination.
Q2. in p-type semiconductor
Answer : Option B
Explaination / Solution:
P-type semiconductors have a larger hole concentration than electron concentration. The term P-type refers to the positive charge of the hole.
In P-type semiconductors, holes are the majority carriers and electrons are the minority carriers. P-type semiconductors are created by doping an intrinsic semiconductor with acceptor impurities (or doping an n-type semiconductor).
A common P-type dopant for silicon is boron. For P-type semiconductors the Fermi level is below the intrinsic Fermi level and lies closer to the valence band than the conduction band.
Q3. The Voltage Source Inverter (VSI) shown in the figure below is switched to provide a 50 Hz, square-wave
ac output voltage (v0) across an R-L load. Reference polarity of v0 and reference direction of the output
current i0 are indicated in the figure. It is given that R = 3 Ω, L = 9.55 mH.
In the interval when v0 < 0 and i0 > 0 the pair of devices which conducts the load current is
Answer : Option D
Explaination / Solution:
No Explaination.
Q4. What is the minimal form of the Karnaugh map shown below? Assume that X denotes a don’t
care term.
Answer : Option B
Explaination / Solution:
Q5. The nature of feedback in the op-amp circuit shown is
Answer : Option B
Explaination / Solution:
No Explaination.
Q6. The SOP (sum of products) form of a Boolean function is Σ(0,1,3,7,11), where inputs are A,B,C,D (A is MSB, and D is LSB). The equivalent minimized expression of the function is
Answer : Option A
Explaination / Solution:
Q7. The electric dipole potential falls off, at large distance r
Answer : Option D
Explaination / Solution:
The potential due to a dipole at a point (r ,θ)from its center is therefore,
Q8. The drain current of MOSFET in saturation is given by 
where K is a constant.
where K is a constant. The magnitude of the transconductance gm is
Answer : Option B
Explaination / Solution:
Q9. The magnetic field at the center of a solenoid coil having n turns and carrying a current I in air is
Answer : Option B
Explaination / Solution:
The magnetic field at the centre of a solenoid with air core is .where,is the permeability of free space, n the number of turns per unit length and I is the current flowing through the solenoid.
Q10. The slope and level detector circuit in a CRO has a delay of 100 ns. The start-stop sweep generator has a response time of 50 ns. In order to display correctly, a delay line of
Answer : Option A
Explaination / Solution:
The delay line should be inverted in VDP (Y-channel) only.
