Electronic Science - Online Test
Q1. Which of the following is NOT associated with a p - n junction ?
Answer : Option D
Explaination / Solution:
Channel length modulation is not associated with a p - n junction. It is being associated with MOSFET in which effective channel length decreases, producing the phenomenon called channel length modulation.
Q2. cyclotron is used to
Answer : Option B
Explaination / Solution:
Cyclotron is a particle accelerator, which uses electric field to accelerate the charged particle and magnetic field to make it move in a circular path. During acceleration in the electric field, the particle acquires high energies of the order of a few million electron volts.
Q3. For the circuit shown below, taking the opamp as ideal, the output voltage Vout in terms of the input
voltages V1 , V2 and V3 is
Answer : Option D
Explaination / Solution:
Q4. An ammeter together with an unknown resistance in series is connected across two identical batteries each of emf 1.5 V. When the batteries are connected in series, the galvanometer records a current of 1A and when the batteries are in parallel, the current is 0.6A. Then the internal resistance of the battery is
Answer : Option B
Explaination / Solution:
When the batteries are in series, the internal resistances are in series. Both e m f and the internal resistances add up.
from equation (i) and (ii)
Q5. In the 3-phase inverter circuit shown, the load is balanced and the gating scheme is 1800 -conduction mode. All the switching devices are ideal
If the dc bus voltage Vd = 300 V, the power consumed by 3-phase load is
Answer : Option D
Explaination / Solution:
Q6. According to Gauss’s law for magnetism
Answer : Option D
Explaination / Solution:
No Explaination.
Q7. In n-type semiconductor the total number of conduction electrons is due to the,
Answer : Option D
Explaination / Solution:
When pentavalent impurity is added to an intrinsic or pure semiconductor (silicon or germanium), then it is said to be an n-type semiconductor. Pentavalent impurities such as phosphorus, arsenic, antimony etc are called donor impurity.
In n-type semiconductor, the population of free electrons is more whereas the population of holes is less. Hence in n-type semiconductor free electrons are called majority carriers and holes are called minority carriers. Therefore, in a n-type semiconductor conduction is mainly because of motion of free electrons.
Q8. The decimal value 0.5 in IEEE single precision floating point representation has
Answer : Option B
Explaination / Solution:
(0.5)10 = (1.0)2 × 2-1
So, exponent = -1 and fraction is 000 - - - 000
Q9. 
The clock frequency applied to the digital circuit shown in the figure below is 1kHz. If the initial state of the output of the flip-flop is 0, then the frequency of the output waveform Q in kHz is
Answer : Option B
Explaination / Solution:
No Explaination.
Q10. A strain gauge forms one arm of the bridge shown in the figure below and has a nominal resistance
without any load as Rs = 300 Ω. Other bridge resistances are R1 = R2 = R3 = 300 Ω. The maximum
permissible current through the strain gauge is 20 mA. During certain measurement when the
bridge is excited by maximum permissible voltage and the strain gauge resistance is increased by
1% over the nominal value, the output voltage V0 in mV is
Answer : Option C
Explaination / Solution:
No Explaination.
