Electronic Science - Online Test
Q1. doping of semiconductor is the process of
Answer : Option B
Explaination / Solution:
Doping is the process of adding impurities to intrinsic semiconductors to alter their properties. Normally Trivalent and Pentavalent elements are used to dope Silicon and Germanium. When an intrinsic semiconductor is doped with Trivalent impurity it becomes a P-Type semiconductor.
Q2. 
The filters F1 and F2 having characteristics as shown in Figures (a) and (b) are connected as shown in Figure (c).
The cut-off frequencies of F1 and F2 are f1 and f2 respectively. If f1 < f2 the resultant
circuit exhibits the characteristics of a
Answer : Option B
Explaination / Solution:
No Explaination.
Q3. The saturation voltage of the ideal op-amp shown below is ±10V. The output voltage v0 of
the following circuit in the steady-state is
Answer : Option A
Explaination / Solution:
Q4. If a positive charge moves opposite to the direction of the electric field
Answer : Option D
Explaination / Solution:
A positive charge experiences a force in the direction of the field. If it moves opposite to the direction of the field, negative work is done by the electric field on the charge. Potential energy of the charge increases since an external source is required to do work on the charge against the direction of the field, and the work done is stored in the charge as its potential energy.
Q5. The figure shows the high-frequency capacitance - voltage characteristics of Metal/Sio2/silicon (MOS) capacitor having an area of 1 × 10-4 cm2. Assume that the permittivities (ε0εr) of silicon and Sio are 1 × 10-12 F/cm and 3.5 × 10-13 F/ cm respectively.
The gate oxide thickness in the MOS capacitor is
Answer : Option A
Explaination / Solution:
Q6. The input voltage given to a converter is
The current drawn by the converter is
The input power factor of the converter is
Answer : Option C
Explaination / Solution:
Q7. correct expression for force on a current carrying conductor of length dl in a magnetic field is
Answer : Option B
Explaination / Solution:
force experienced by a conductor of length l carrying current I placed in magnetic field B is given by .Here =
Q8. The minimum number of D flip-flops needed to design a mod-258 counter is
Answer : Option A
Explaination / Solution:
2n ≥ 258 ⇒ n = 9
Q9. A half-controlled single-phase bridge rectifier is supplying an R-L load. It is operated at a firing angle α and the load current is continuous. The fraction of cycle that the freewheeling diode conducts is
Answer : Option D
Explaination / Solution:
No Explaination.
Q10. The output Y of a 2-bit comparator is logic 1 whenever the 2-bit input A is greater than the 2-bit input B. The number of combinations for which the output is logic 1, is
Answer : Option B
Explaination / Solution:
