Test: Electronic Devices - 1 | 15 Questions MCQ Test GATE ECE (Electronics) 2023 Mock Test Series Electronics and Communication Engineering (ECE)

QUESTION: 1

A BJT with one junction forward biased and either Emitter or collector is open operates in

A.
Cut-off
B.
Active
C.
Saturation
D.
Pinch-off

Solution:

Charge storage will be positive and higher so it must enter into saturation.

QUESTION: 2

A, N-channel Si (εr = 12) FET with a channel width a = 2 × 10⁻⁶ meter is doped with 10²¹ e’s / m3. The value of pinch-off voltage is _________ V.

A.
3.0
B.
1.0
C.
11
D.
3.02

Solution:

QUESTION: 3

A diode which is in reverse bias at 3 volt has a junction capacitance of 20 pF when reverse bias is increased to 24 volt then junction capacitance becomes 8 pF. The doping profile and contact potential are

A.
Linear graded V₀ = 1 volt
B.
Linear graded V₀ = 2 volt
C.
Step graded V₀ = 1 volt
D.
Step graded V₀ = −1 volt

Solution:

QUESTION: 4

A potential difference of 5 volt is applied across a uniform wire of length 50 meter. Calculate drift velocity of electrons through the wire, If relaxation time is 10⁻¹⁴ sec. (Given Mass of electron, m = 9.1 × 10⁻³¹ kg)

A.
0.176 × 10⁻³ m/s
B.
0.95 m/s
C.
1.76 × 10⁻⁵ m/s
D.
1.5 × 10⁻⁶ m/s

Solution:

QUESTION: 5

For an ideal Ge forward bias diode, the change in diode voltage to increase forward bias diode current 10 times is _________ mV.

A.
60.2
B.
59.6
C.
24.25
D.
58.36

Solution:

QUESTION: 6

Which one of the following statements is correct?In the context of I.C. fabrication metallization means

A.
Connecting metallic wires
B.
Formation of inter connecting conduction pattern and bonding pads
C.
Doping S_ioz layer
D.
covering with a metallic cap

Solution:

Formation of inter connecting conduction pattern and bounding pads

QUESTION: 7

If two FET's are connected in parallel and have µ₁ = 2, µ₂ = 3 and rd₁ = 2 kΩ, rd₂ = 3 kΩ, what is equivalent value of µ and rd.

A.
2.4, 1.2 kΩ
B.
1.2, 5 kΩ
C.
5, 1.2 kΩ
D.
1, 5 kΩ

Solution:

QUESTION: 8

Which of the following semi-conductors are used for solar-cells?

1. Si 2. Ge 3. GaAs 4. CdS

A.
1, 2, 4
B.
1, 2, 3
C.
1, 3, 4
D.
1, 2, 3, 4

Solution:

QUESTION: 9

Temp. Coefficient of resistivity in an Intrinsic Semiconductor is

A.
Positive and has a large value
B.
Negative and has a large value
C.
Positive and has a small value
D.
Negative and has a small value

Solution:

QUESTION: 10

Under low level injection assumption, the main driving current in an extrinsic semiconductor of n-type is

A.
hole drift current, electron drift current and electron diffusion current
B.
hole diffusion current, electron diffusion current
C.
hole drift current, hole diffusion current
D.
hole diffusion current, electron drift current and electron diffusion current

Solution:

Under low level injection, hold drift current being directly proportional to concentration of holes is negligible.

QUESTION: 11

The following statements are related to a tunnel diode

1. Fermi level in n-side lies inside valence band

2. Excellent conduction is possible in reverse bias

3. In reverse bias negative resistance is exhibited

4. V_P > V_V

5. It can act as oscillator

6. The magnitude of lP is decided by impurity concentration and Junction area

7. Ge tunnel diode is used for commercial applications

Which of the above statements are false?

A.
1, 3 & 4
B.
1, 3, 4 & 7
C.
1, 3, 4, 6 & 7
D.
2, 5, 6 & 7

Solution:

QUESTION: 12

For a NPN transistor which operates in active region then main stream of current in base is

A.
Diffusion of holes
B.
Drift of electrons
C.
Drift of holes
D.
Diffusion of electrons

Solution:

QUESTION: 13

Which of the following diodes work under reverse bias condition? 1. Zener 2. Varacter 3. Photo diode 4. LED

A.
1, 3
B.
1, 3, 4
C.
1, 2, 3
D.
1, 2, 3, 4

Solution:

LED works in forward biased condition.

QUESTION: 14

In a forward bias photodiode an increase in incident light intensity causes diode current to

A.
Increase
B.
Remains constant
C.
Decrease
D.
Remains constant, while voltage drop across diode increases

Solution:

Due to light new electrons and hole pairs are produced.

QUESTION: 15

In an unbiased P-N Junction zero current implies that

A.
The potential biases has disappeared
B.
No. of holes diffusing from P-side to N-side equals the no. of electrons diffusing from N-side to P-side
C.
Total current crossing Junction from P-side to N-side equals the total current crossing Junction from N-side top-side
D.
No carriers cross the Junction

Solution:

Test: Electronic Devices - 1

15 Questions MCQ Test GATE ECE (Electronics) 2023 Mock Test Series | Test: Electronic Devices - 1

A BJT with one junction forward biased and either Emitter or collector is open operates in

A, N-channel Si (εr = 12) FET with a channel width a = 2 × 10⁻⁶ meter is doped with 10²¹ e’s / m3. The value of pinch-off voltage is _________ V.

A diode which is in reverse bias at 3 volt has a junction capacitance of 20 pF when reverse bias is increased to 24 volt then junction capacitance becomes 8 pF. The doping profile and contact potential are

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