BITSAT Physics Semiconductor Electronics Materials Devices and Simple Circuits MCQs

Question: In the circuit given below, V(t) is the sinusoidal voltage source, voltage drop V_AB(t) across the resistance R is

• a) Is half wave rectified
• b) Is full wave rectified
• c) Has the same peak value in the positive and negative half cycles
• d) Has different peak values during positive and negative half cycle

Answer: Has different peak values during positive and negative half cycle

Question: In CE transistor amplifier, the audio signal voltage across the collector resistance of 2 kΩ is 2 V. If the base resistance is 1kΩ and the current amplification of the transistor is 100, the input signal voltage is

• a) 2 mV
• b) 3 mV
• c) 10 mV
• d) 0.1 mV

Answer: 10 mV

Question: An oscillator is nothing but an amplifer with

• a) Positive feedback
• b) Negative feedback
• c) Large gain
• d) No feedback

Answer: Positive feedback

Question: Assuming the diodes to be of silicon with forward resistance zero, the current I in the following circuit is

• a) 0
• b) 9.65 mA
• c) 10 mA
• d) 10.35 mA

Answer: 10 mA

Question: For a CE transistor amplifier, the audio signal voltage across the collector resistance of 2.0 kΩ is 2.0 V. Suppose the current amplification factor of the transistor is 100, What should be the value of R_B in series with V_BB supply of 2.0V if the dc base current has to be 10 times the signal current?

• a) 14 kΩ
• b) 18 kΩ
• c) 10 kΩ
• d) 5 kΩ

Answer: 14 kΩ

Question: The combination of gates shown below yields

• a) OR gate
• b) NOT gate
• c) XOR gate
• d) NAND gate

Answer: OR gate

Question: Transfer characteristics [output voltage (V₀) vs input voltage (V₁)] for a base biased transistor in CE configuration is as shown in the figure. For using transistor as a switch, it is used

• a) in region (III)
• b) both in region (I) and (III)
• c) in region (II)
• d) in region (I)

Answer: both in region (I) and (III)

Question: If in a p-n junction diode, a square input signal of 10 V is applied as shown 

Then the output signal across R_L will be

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The output of an OR gate is connected to both the inputs of a NAND gate. The combination will serve as a:

• a) NOT gate
• b) NOR gate
• c) AND gate
• d) OR gate

Answer: NOR gate

Question: In a semiconductor diode, the barrier potential offers opposition to

• a) Holes in P-region only
• b) Free electrons in N-region only
• c) Majority carriers in both regions
• d) Majority as well as minority carriers in both regions

Answer: Majority carriers in both regions

Question: A transistor has a base current of 1 mA and emitter current 90 mA. The collector current will be

• a) 90 mA
• b) 1 mA
• c) 89 mA
• d) 91 mA

Answer: 89 mA

Question: A d.c. battery of V volt is connected to a series combination of a resistor R and an ideal diode D as shown in the figure below. The potential difference across R will be

• a) 2V when diode is forward biased
• b) Zero when diode is forward biased
• c) V when diode is reverse biased
• d) V when diode is forward biased

Answer: V when diode is reverse biased

Question: Truth table for system of four NAND gates as shown in figure is :

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: In a common base amplifier the phase difference between the input signal voltage and the output voltage is

• a) 0
• b) π/4
• c) π/2
• d) π

Answer: 0

Question: A zener diode, having breakdown voltage equal to 15V, is used in a voltage regulator circuit shown in figure. The current through the diode is

• a) 10 mA
• b) 15 mA
• c) 20 mA
• d) 5 mA

Answer: 5 mA

Question: In an unbiased n-p junction electrons diffuse from n-region to p-region because :

• a) Holes in p-region attract them
• b) Electrons travel across the junction due to potential difference
• c) Only electrons move from n to p region and not the vice-versa
• d) Electron concentration in n-region is more compared to that in p-region

Answer: Electron concentration in n-region is more compared to that in p-region

Question: In common emitter amplifier, the current gain is 62. The collector resistance and input resistance are 5 kΩ an 500Ω respectively. If the input voltage is 0.01 V, the output voltage is

• a) 0.62 V
• b) 6.2 V
• c) 62 V
• d) 620 V

Answer: 6.2 V

Question: An oscillator is nothing but an amplifer with

• a) Positive feedback
• b) Negative feedback
• c) Large gain
• d) No feedback

Answer: Positive feedback

Question: The output of an OR gate is connected to both the inputs of a NAND gate. The combination will serve as a:

• a) NOT gate
• b) NOR gate
• c) AND gate
• d) OR gate

Answer: NOR gate

Question: In a semiconductor diode, the barrier potential offers opposition to

• a) Holes in P-region only
• b) Free electrons in N-region only
• c) Majority carriers in both regions
• d) Majority as well as minority carriers in both regions

Answer: Majority carriers in both regions