PU CET Lahore (Engineering & CS) Physics: Past Papers MCQs with Answers

PU CET Lahore (Engineering & CS) Physics Past Papers sample MCQs

1. Q1. In an AC circuit, the voltage is given by V = 200 sin(100πt) and the current is given by I = 10 sin(100πt + π/3). What is the power factor?

   • A) 0.5
   • B) 0.866
   • C) 1
   • D) 0

   Answer: 0.5

2. Q2. A coil is rotated in a magnetic field. The emf induced is maximum when the coil is

   • A) parallel to the field
   • B) perpendicular to the field
   • C) at 45° to the field
   • D) at 60° to the field

   Answer: parallel to the field

3. Q3. A 10 V battery is connected to a 5 ohm resistor. The current is

   • A) 1 A
   • B) 2 A
   • C) 0.5 A
   • D) 5 A

   Answer: 2 A

4. Q4. The unit of electric flux is

   • A) N m² / C
   • B) N / C
   • C) V m
   • D) V / m

   Answer: N m² / C

5. Q5. Absolute error in the above measurements?

   • A) 0.005
   • B) 0.01
   • C) 0.02
   • D) 0.03

   Answer: 0.01

6. Q6. A mass-spring system has a time period of 2 s. What is its frequency?

   • A) 0.5 Hz
   • B) 1 Hz
   • C) 2 Hz
   • D) 4 Hz

   Answer: 0.5 Hz

7. Q7. A series LCR circuit is in resonance. What is the impedance of the circuit?

   • A) R
   • B) L
   • C) C
   • D) L + C

   Answer: R

8. Q8. In an LCR circuit, the voltage across L, C, and R are 20 V, 20 V, and 40 V, respectively. The supply voltage is

   • A) 40 V
   • B) 20 V
   • C) 60 V
   • D) 80 V

   Answer: 40 V

9. Q9. The current in an AC circuit is given by I = 5 sin(100t - π/4). The rms value is

   • A) 5/√2 A
   • B) 5√2 A
   • C) 5 A
   • D) 2.5 A

   Answer: 5/√2 A

10. Q10. The impedance of a coil is 10 Ω at 50 Hz. At 100 Hz, it is

    • A) 20 Ω
    • B) 10 Ω
    • C) > 10 Ω
    • D) < 10 Ω

    Answer: > 10 Ω

11. Q11. A capacitor of capacitance 1 μF is connected to an AC source of 220 V, 50 Hz. The rms current is

    • A) 6.9 mA
    • B) 69 mA
    • C) 0.69 A
    • D) 6.9 A

    Answer: 69 mA

12. Q12. The voltage across a resistor in an AC circuit is 100 V. The current is

    • A) 100/R A
    • B) 100√2/R A
    • C) 100/R√2 A
    • D) R/100 A

    Answer: 100/R√2 A

13. Q13. The wattless current in an AC circuit is

    • A) Irms * cosφ
    • B) Irms * sinφ
    • C) Irms
    • D) 0

    Answer: Irms * sinφ

14. Q14. In a series RC circuit, the voltage across the capacitor is 100 V and across the resistor is 100 V. The supply voltage is

    • A) 100√2 V
    • B) 200 V
    • C) 100 V
    • D) 141.4 V

    Answer: 100√2 V

15. Q15. At resonance, the impedance of a series LCR circuit is

    • A) Maximum
    • B) Minimum
    • C) Zero
    • D) Infinite

    Answer: Minimum

16. Q16. The current in an AC circuit is given by I = 5 sin(100πt + π/4). The frequency is

    • A) 50 Hz
    • B) 100 Hz
    • C) 25 Hz
    • D) 200 Hz

    Answer: 50 Hz

17. Q17. The voltage across a resistor is given by V = 100 sin(50πt). The rms voltage is

    • A) 70.7 V
    • B) 100 V
    • C) 50 V
    • D) 200 V

    Answer: 70.7 V

18. Q18. In an LCR circuit, the voltage across the inductor is 100 V, across the capacitor is 50 V, and across the resistor is 50 V. The supply voltage is

    • A) 100 V
    • B) 50 V
    • C) 70.7 V
    • D) 150 V

    Answer: 70.7 V

19. Q19. The resonant frequency of a series LCR circuit is given by

    • A) 1/(2π√(LC))
    • B) 1/(2πLC)
    • C) √(L/C)/(2π)
    • D) 2π√(LC)

    Answer: 1/(2π√(LC))

20. Q20. The reactance of an inductor is given by

    • A) ωL
    • B) 1/(ωL)
    • C) ω/C
    • D) 1/(ωC)

    Answer: ωL

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