NTS NAT-IM (Medical / Pre-Medical Track) Physics Electronics — Set 2

Electronics MCQs set 2 for NTS NAT-IM (Medical / Pre-Medical Track) Physics — 20 solved questions.

NTS NAT-IM (Medical / Pre-Medical Track) Physics Electronics — Set 2

  1. Question 1

    Q1. A sinusoidal voltage of peak value 10 V is applied to a diode and a 1 kΩ resistor in series. What is the peak current?

    • A) 10 mA
    • B) 0 A
    • C) 5 mA
    • D) 20 mA

    Answer: 10 mA

    Explanation: Peak current = peak voltage / resistance = 10 V / 1 kΩ = 10 mA. Diode is forward biased.

  2. Question 2

    Q2. A transistor has a current gain of 50. If the base current is 20 μA, what is the collector current?

    • A) 1 mA
    • B) 0.5 mA
    • C) 1.5 mA
    • D) 2 mA

    Answer: 1 mA

    Explanation: Collector current = current gain * base current = 50 * 20 μA = 1 mA.

  3. Question 3

    Q3. A capacitor of 100 nF is connected in parallel with a resistor of 1 kΩ. What is the impedance at a frequency of 1 kHz?

    • A) 1591 Ω
    • B) 1000 Ω
    • C) 796 Ω
    • D) 500 Ω

    Answer: 796 Ω

    Explanation: Xc = 1 / (2πfC) = 1591 Ω. Z = (R * Xc) / sqrt(R^2 + Xc^2) = 796 Ω.

  4. Question 4

    Q4. A full-wave rectifier is used to rectify an AC voltage of rms value 12 V. What is the average DC output voltage?

    • A) 10.8 V
    • B) 12 V
    • C) 15.3 V
    • D) 8.5 V

    Answer: 10.8 V

    Explanation: Vrms = 12 V, Vpeak = 12 * sqrt(2) = 16.97 V. Vdc = 0.637 * Vpeak = 10.8 V.

  5. Question 5

    Q5. A logic gate produces an output of 1 only when both inputs are 1. What type of gate is it?

    • A) AND
    • B) OR
    • C) NOT
    • D) XOR

    Answer: AND

    Explanation: AND gate produces 1 only when both inputs are 1.

  6. Question 6

    Q6. A silicon diode has a voltage drop of 0.7 V when forward biased. What is the voltage drop across the diode when a 5 V battery is connected in series with the diode and a 1 kΩ resistor?

    • A) 0.7 V
    • B) 5 V
    • C) 4.3 V
    • D) 0 V

    Answer: 0.7 V

    Explanation: Voltage drop across diode remains 0.7 V as it is forward biased.

  7. Question 7

    Q7. A transistor amplifier has a voltage gain of 100. If the input voltage is 10 mV, what is the output voltage?

    • A) 1 V
    • B) 0.1 V
    • C) 10 V
    • D) 0.01 V

    Answer: 1 V

    Explanation: Output voltage = voltage gain * input voltage = 100 * 10 mV = 1 V.

  8. Question 8

    Q8. A circuit consists of a 10 kΩ resistor and a 100 nF capacitor in series. What is the time constant?

    • A) 1 ms
    • B) 0.1 ms
    • C) 10 ms
    • D) 100 ms

    Answer: 1 ms

    Explanation: Time constant = RC = 10 kΩ * 100 nF = 1 ms.

  9. Question 9

    Q9. A half-wave rectifier is used to rectify an AC voltage of peak value 20 V. What is the peak inverse voltage?

    • A) 20 V
    • B) 10 V
    • C) 40 V
    • D) 0 V

    Answer: 20 V

    Explanation: Peak inverse voltage = peak value of AC voltage = 20 V.

  10. Question 10

    Q10. A NAND gate produces an output of 0 when

    • A) both inputs are 0
    • B) both inputs are 1
    • C) one input is 0 and the other is 1
    • D) both inputs are 1 or one input is 0 and the other is 1

    Answer: both inputs are 1

    Explanation: NAND gate produces 0 only when both inputs are 1.

  11. Question 11

    Q11. A Zener diode is used as a voltage regulator. If the Zener voltage is 5 V, what is the output voltage?

    • A) 5 V
    • B) 10 V
    • C) 0 V
    • D) Variable

    Answer: 5 V

    Explanation: Output voltage = Zener voltage = 5 V.

  12. Question 12

    Q12. A common-emitter amplifier has a current gain of 50. If the base current is changed by 10 μA, what is the change in collector current?

    • A) 0.5 mA
    • B) 1 mA
    • C) 0.1 mA
    • D) 5 mA

    Answer: 0.5 mA

    Explanation: Change in collector current = current gain * change in base current = 50 * 10 μA = 0.5 mA.

  13. Question 13

    Q13. A filter circuit is used to remove AC ripples from a rectified voltage. What type of filter is commonly used?

    • A) Capacitor filter
    • B) Inductor filter
    • C) LC filter
    • D) RC filter

    Answer: Capacitor filter

    Explanation: Capacitor filter is commonly used to remove AC ripples.

  14. Question 14

    Q14. A logic circuit has three inputs A, B, and C. The output is 1 when A and B are 1 or when C is 1. What is the logic gate?

    • A) AND
    • B) OR
    • C) XOR
    • D) Combination of AND and OR

    Answer: Combination of AND and OR

    Explanation: The output is 1 when A and B are 1 (AND operation) or when C is 1 (OR operation), so it's a combination of AND and OR.

  15. Question 15

    Q15. A transistor has a base current of 20 μA and a collector current of 1 mA. What is the emitter current?

    • A) 1.02 mA
    • B) 1 mA
    • C) 0.98 mA
    • D) 2 mA

    Answer: 1.02 mA

    Explanation: Emitter current = collector current + base current = 1 mA + 20 μA = 1.02 mA.

  16. Question 16

    Q16. A diode is used to rectify an AC voltage. What is the purpose of the diode?

    • A) To amplify the voltage
    • B) To regulate the voltage
    • C) To convert AC to DC
    • D) To filter the voltage

    Answer: To convert AC to DC

    Explanation: Diode is used to convert AC to DC (rectification).

  17. Question 17

    Q17. A voltage regulator is used to regulate an input voltage of 12 V to an output voltage of 5 V. What is the type of regulator?

    • A) Step-up regulator
    • B) Step-down regulator
    • C) Linear regulator
    • D) Switching regulator

    Answer: Step-down regulator

    Explanation: Output voltage (5 V) is less than input voltage (12 V), so it's a step-down regulator.

  18. Question 18

    Q18. A circuit consists of a 1 kΩ resistor and a 100 nF capacitor in series. What is the cutoff frequency?

    • A) 1591 Hz
    • B) 1000 Hz
    • C) 796 Hz
    • D) 500 Hz

    Answer: 1591 Hz

    Explanation: Cutoff frequency = 1 / (2πRC) = 1591 Hz.

  19. Question 19

    Q19. A digital circuit has four inputs. What is the minimum number of NAND gates required to implement the circuit?

    • A) 4
    • B) 5
    • C) 6
    • D) It depends on the specific circuit

    Answer: It depends on the specific circuit

    Explanation: The number of NAND gates required depends on the specific digital circuit.

  20. Question 20

    Q20. A transistor amplifier has an input resistance of 1 kΩ and an output resistance of 10 kΩ. What is the voltage gain?

    • A) 10
    • B) 100
    • C) 50
    • D) It depends on the current gain

    Answer: It depends on the current gain

    Explanation: Voltage gain depends on current gain and resistance gain.

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Level 1

A sinusoidal voltage of peak value 10 V is applied to a diode and a 1 kΩ resistor in series. What is the peak current?