Semiconductor Electronics: Materials, Devices and Simple Circuits Test 70

Result

Semiconductor Electronics: Materials, Devices and Simple Circuits Test 70

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Weekly Quiz Competition

Question 1
1 / -0

The logic which produces LOW output when one of the input is HIGH and produces HIGH output only when all its inputs are LOW is called _.

A
AND gate

B
OR gate

C
NOR gate

D
NAND gate

Solution
Question 2
1 / -0

In the resistance box, a double wired coil is fixed as shown in the figure so that :-

A
The wire may not be heated

B
The wire may not break easily

C
Electromagnetic induction may increase

D
Self induction in the coil may be negligible

Solution
Question 3
1 / -0

For a diode connected in parallel with a resistor, which is the most likely current (I) -voltage (V) characteristics?

A

B

C

D

Solution

When the value of V is +ve, the diode is forward biased. Thus, the current flowing through the diode is exponential and the current in the resistor varies linearly. Thus, the V−I characteristic is an exponential curve when $$V>0$$
When the value of V is -ve, the diode is reverse biased. Thus, no current flows through it and the current in the resistor varies linearly with voltage (Ohm's law). Thus, the V−I characteristic is a straight line when $$V<0$$
So, the correct answer is option (A).
Question 4
1 / -0

The output of the given logic circuit is

A
$$AB+\overline { AB } $$

B
$$A\overline { B } $$

C
$$\overline { A } B$$

D
$$A\overline { B } +\overline { A } B$$

Solution
Question 5
1 / -0

In figure the approximate value of $$V_o$$ across the diode is

A
zero

B
5V

C
2.5 V

D
depends on the size of R
Question 6
1 / -0

If in a p-n junction diode, a square input signal of $$10V$$ is applied as shown. Then, the output signal across $${R}_{L}$$ will be-

A

B

C

D

Solution
Question 7
1 / -0

Shown in the figure is a combination of logic gates. The output values at $$P$$ and $$Q$$ are correctly represented by which of the following?

A
$$0,0$$

B
$$1,1$$

C
$$0,1$$

D
$$1,0$$

Solution
Question 8
1 / -0

Which one is in forward bias :

A

B

C

D
None of these

Solution

In forward bias of a diode the $$P$$-end must be connected to the positive terminal of the battery and the $$N$$-end is connected to the negative terminal of the battery.
So, option (B) is correct.
Question 9
1 / -0

Which of the following P-N junction diode is reverse biased

A

B

C

D

Solution

Current only flows from a higher potential to a lower potential. Also, the ends of the circuit that are grounded remain at zero potential.
In cases (A), (C) & (D), the diodes are connected in the forward bias.
In case (B), the $${\text{p - }}$$side is connected to the lower potential, and $${\text{n - }}$$side is connected to the higher potential, suggesting that the diode is in reverse bias.
Question 10
1 / -0

The resistivity of a pure semiconductor is $$0.5 \Omega\ m$$. If the electron and hole mobility be $$0.39$$ $$m^2/V-s$$ and $$0.19$$ $$m^2/V-s$$ respectively then calculate the intrinsic carrier concentration.

A
$$2.16 \times 10^{19} /m^3$$

B
$$4.64 \times 10^{18} /m^3$$

C
$$ 10^{20} /m^3$$

D
$$none\ of\ these$$

Solution

The resistivity of the semiconductor, $$\rho = 0.5{\text{ }}\Omega m$$
The charge of electron, $${q_e} = 1.6 \times {10^{ - 19}}{\text{ C}}$$
The electron mobility, $${\mu _e} = 0.39{\text{ }}{{\text{m}}^2}{{\text{V}}^{{\text{ - 1}}}}{{\text{s}}^{{\text{ - 1}}}}$$
The hole mobility, $${\mu _h} = 0.19{\text{ }}{{\text{m}}^2}{{\text{V}}^{{\text{ - 1}}}}{{\text{s}}^{{\text{ - 1}}}}$$
Now,
$$\frac{1}{\mu } = {q_e}\left( {{n_i}{\mu _e} + {n_i}{\mu _h}} \right)$$
$${n_i} = \frac{1}{{\mu .{q_e}\left( {{\mu _e} + {\mu _h}} \right)}}$$
$${n_i} = \frac{1}{{\left( {0.5{\text{ }}\Omega m} \right).\left( {1.6 \times {{10}^{ - 19}}{\text{ C}}} \right)\left( {\left( {0.39 + 0.19} \right){{\text{m}}^2}{{\text{V}}^{{\text{ - 1}}}}{{\text{s}}^{{\text{ - 1}}}}} \right)}}$$
$${n_i} = 4.64 \times {10^{18}}{\text{ }}{{\text{m}}^{ - 3}}$$