Technical Basics PYQ
Technical Basics - Previous Year Questions
20 authentic PYQ-style questions.
Use format:
- Question with 4 options
- Answer, solution, exam year tag [2018-2024]
1. The unit of electric current is:
Options:
A. Volt
B. Ohm
C. Ampere
D. Joule
Answer: C. Ampere
Solution: The SI unit of electric current is Ampere (A).
Tag: [2022]
2. Which material is commonly used as a semiconductor?
Options:
A. Copper
B. Silicon
C. Aluminium
D. Iron
Answer: B. Silicon
Solution: Silicon is widely used in semiconductor devices due to its stable properties.
Tag: [2021]
3. The power factor of a purely resistive circuit is:
Options:
A. 0
B. 0.5
C. 1
D. -1
Answer: C. 1
Solution: In a purely resistive circuit, voltage and current are in phase, so power factor = 1.
Tag: [2020]
4. Which of the following is a passive component?
Options:
A. Transistor
B. Diode
C. Resistor
D. Op-amp
Answer: C. Resistor
Solution: Resistors do not require external power to operate, hence they are passive.
Tag: [2019]
5. The colour code for a 1 kΩ ±5% resistor is:
Options:
A. Brown-Black-Red-Gold
B. Brown-Black-Brown-Silver
C. Red-Red-Brown-Gold
D. Brown-Black-Orange-Gold
Answer: A. Brown-Black-Red-Gold
Solution: Brown=1, Black=0, Red=2 zeros → 1000 Ω, Gold=±5%.
Tag: [2021]
6. A capacitor blocks:
Options:
A. AC
B. DC
C. Both AC and DC
D. None
Answer: B. DC
Solution: Capacitive reactance Xc = 1/(2πfC); for DC, f = 0 ⇒ Xc → ∞.
Tag: [2018]
7. The gate that gives HIGH output only when both inputs are LOW is:
Options:
A. NAND
B. NOR
C. XOR
D. AND
Answer: B. NOR
Solution: NOR gives HIGH only when both inputs are LOW.
Tag: [2020]
8. A step-down transformer has:
Options:
A. Np > Ns
B. Np < Ns
C. Np = Ns
D. Np = 0
Answer: A. Np > Ns
Solution: Step-down means fewer secondary turns ⇒ Np > Ns.
Tag: [2022]
9. Which diode is used for voltage regulation?
Options:
A. PN junction
B. Zener
C. Varactor
D. Schottky
Answer: B. Zener
Solution: Zener diode operates in reverse breakdown for regulation.
Tag: [2021]
10. The frequency of domestic AC supply in India is:
Options:
A. 50 Hz
B. 60 Hz
C. 40 Hz
D. 100 Hz
Answer: A. 50 Hz
Solution: Standard Indian grid frequency is 50 Hz.
Tag: [2019]
11. Ohm’s law is valid for:
Options:
A. Linear & bilateral
B. Non-linear
C. Unilateral
D. Only resistors
Answer: A. Linear & bilateral
Solution: Ohm’s law holds for linear bilateral elements.
Tag: [2020]
12. The reactance of a 100 µF capacitor at 50 Hz is:
Options:
A. 31.8 Ω
B. 3.18 Ω
C. 318 Ω
D. 0.318 Ω
Answer: A. 31.8 Ω
Solution: Xc = 1/(2πfC) = 1/(2π×50×100×10⁻⁶) ≈ 31.8 Ω.
Tag: [2023]
13. A triac is equivalent to:
Options:
A. Two SCRs in anti-parallel
B. Two diodes in series
C. One SCR & one diode
D. Two SCRs in series
Answer: A. Two SCRs in anti-parallel
Solution: Triac conducts in both directions → anti-parallel SCR pair.
Tag: [2022]
14. The decimal equivalent of binary 11010 is:
Options:
A. 24
B. 26
C. 28
D. 30
Answer: B. 26
Solution: 1×2⁴ + 1×2³ + 0×2² + 1×2¹ + 0×2⁰ = 16+8+0+2+0 = 26.
Tag: [2021]
15. Which motor is NOT self-starting?
Options:
A. 3-phase induction
B. Single-phase induction
C. DC shunt
D. DC series
Answer: B. Single-phase induction
Solution: Single-phase IM needs aux winding/capacitor for starting torque.
Tag: [2020]
16. The time constant of an RL circuit is:
Options:
A. R/L
B. L/R
C. RC
D. 1/RC
Answer: B. L/R
Solution: τ = L/R seconds.
Tag: [2019]
17. Which sensor is used to measure temperature?
Options:
A. LVDT
B. Thermistor
C. Photodiode
D. Strain gauge
Answer: B. Thermistor
Solution: Thermistor resistance varies with temperature.
Tag: [2023]
18. The Boolean expression A + A̅ equals:
Options:
A. 0
B. 1
C. A
D. A̅
Answer: B. 1
Solution: A + A̅ = 1 (complement law).
Tag: [2022]
19. A 4-bit binary up-counter counts from 0000 to:
Options:
A. 1001
B. 1111
C. 1010
D. 1000
Answer: B. 1111
Solution: 4-bit max = 2⁴ – 1 = 15 → 1111.
Tag: [2021]
20. The main function of a commutator in a DC generator is:
Options:
A. Increase voltage
B. Convert AC to DC
C. Reduce losses
D. Step-up current
Answer: B. Convert AC to DC
Solution: Commutator rectifies AC voltage induced in armature to DC at brushes.
Tag: [2024]
BETA
