Electronic Science - Online Test
Q1. Thin gate oxide in a CMOS process in preferably grown using
Answer : Option B
Explaination / Solution:
Dry oxidation is used to achieve high quality oxide growth.
Q2. 
The fully controlled thyristor converter in the figure is fed from a single-phase source. When the firing angle is 0°, the dc output voltage of the converter is 300V. What will be the output voltage for a firing angle of 60°, assuming continuous conduction?
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. When arsenic is added as an impurity to silicon, the resulting material is
Answer : Option A
Explaination / Solution:
Doping is the process of intentionally introducing impurities into an extremely pure (i.e., intrinsic) semiconductor in order to change its electrical properties. The impurities are dependent upon the type of semiconductor. Lightly and moderately doped semiconductors are referred to as extrinsic semiconductor. A semiconductor which is doped to such high levels that it acts more like a conductor than a semiconductor is called degenerate.
Dopant atoms can either be “donors” or “acceptors.” Donors increase the elctron concentration in the silicon, whereas acceptors increase the hole concentration.
When Arsenic crystal is doped with silicone atoms, then it becomes N-type.
Q4. 
The transfer characteristic for the precision rectifier circuit shown below is (assume ideal OP-AMP and practical diodes)
Answer : Option B
Explaination / Solution:
Q5. 
A parallel plate capacitor consisting two dielectric materials is shown in the figure. The middle dielectric slab is place symmetrically with respect to the plates.
If the potential difference between one of the plates and the nearest surface of dielectric
interface is 2Volts, then the ratio ε1:ε2 is
Answer : Option C
Explaination / Solution:
Q6. If one penetrates a uniformly charged metallic sphere, the electric field strength E
Answer : Option A
Explaination / Solution:
Electric field due to a solid sphere of uniform charge density at points inside the sphere varies asIt decreases at the rate However if the sphere were a hollow shell, the electric field would be zero at all points where r < R
Q7. What should be the current in a circular coil of radius 5 cm to annul BH=5×10−5 T at the center?
Answer : Option C
Explaination / Solution:
The magnetic field produced by the coil at the centre should be equal and opposite to the The field at the centre of a circular coil .The current needed to produce a field equal to
Q8. Meter Bridge is used to
Answer : Option A
Explaination / Solution:
With a known resistance in one of the gaps, the meter bridge is used to determine the value of an unknown resistance by the formula,
where l is the null point.
Q9. If we wanted to cancel the Earth’s magnetic field by running an enormous current loop around the equator, which way would the current have to flow: or west to east?
Answer : Option B
Explaination / Solution:
No Explaination.
Q10. 
The second harmonic component of the periodic waveform given in the figure has an amplitude of
Answer : Option A
Explaination / Solution:
No Explaination.
