Electronic Science - Online Test
Q1. Which of the following is an invalid state in an 8-4-2-1. Binary Coded Decimal counter
Answer : Option D
Explaination / Solution:
In binary coded decimal (BCD) counter the valid states are from 0 to 9 only in binary system 0000 to 1001 only. So, 1100 in decimal it is 12 which is invalid state in BCD counter.
Q2. Match the following:
Instrument Type Used for
P. Permanent magnet moving coil 1. DC only
Q. Moving iron connected through current transformer 2. AC only
R. Rectifier 3.AC and DC
S. Electrodynamometer
Answer : Option C
Explaination / Solution:
No Explaination.
Q3. Electric-field magnitude E at points inside and outside a positively charged spherical conductor having charge Q and a radius R are
Answer : Option B
Explaination / Solution:
Electric field inside a spherical conductor is zero since all the charge resides on the surface of the conductor and there is no charge in the interior of the conductor. For all external points, the conductor behaves as though its entire charge is concentrated at its center.
Q4. In the following limiter circuit, an input voltage Vi = 10 sin100πt is applied.
Assume that the diode drop is 0.7 V when it is forward biased. When it is
forward biased. The zener breakdown voltage is 6.8 V
The maximum and minimum values of the output voltage respectively are
Answer : Option C
Explaination / Solution:
No Explaination.
Q5. what is common to both biot savart law and ampere's law
Answer : Option D
Explaination / Solution:
Both Biot- Savart’s lawand ampere’s circuital lawdeal with the consequences of steady current. Ampere’s circuital law is to Biot- savart’s law as is Gauss’s law to Coulomb’s law in electrostatics.
Q6. In the following figure, C1 and C2 are ideal capacitors. C1 has been charged to 12 V before the ideal
switch S is closed at t = 0. The current i(t) for all t is
Answer : Option D
Explaination / Solution:
Time constant = RC
In the given circuit, R = 0
Rise time = 0; hence capacitor charges instantaneously and the current can be represented as impulse function
Q7. A potential difference of 220 V is maintained across 12000 rheostat. Then voltmeter V has a resistance of 6000 and point C is at one fourth the distance from a to b. Then the reading of voltmeter is
Answer : Option B
Explaination / Solution:
Resistance R = 1/4R = 12000/4 = 3000 parallel. .
This is in series with Rbc.
The current in the circuit I = 220/11000 = 0.02A The reading of the voltmeter is the potential drop across Rp. V = 0.02 * 2000 = 40V
This is in series with Rbc.
The current in the circuit I = 220/11000 = 0.02A The reading of the voltmeter is the potential drop across Rp. V = 0.02 * 2000 = 40V
Q8. magnetic declination and dip refer to
Answer : Option B
Explaination / Solution:
No Explaination.
Q9. in p-type semiconductor the dopant is
Answer : Option D
Explaination / Solution:
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).
Q10. Given that the op-amp is ideal, the output voltage V0 is
Answer : Option B
Explaination / Solution:
No Explaination.
