Top 50 MCQs : Basic Electrical Engineering for Instrument Technicians Quiz

Basic Electrical Engineering Quiz for Instrument Technicians

1. What is the primary purpose of a resistor in an electronic circuit?

a) To store energy b) To oppose the flow of current c) To amplify the signal d) To create a magnetic field

2. Ohm's Law is stated as:

a) V = I/R b) R = V*I c) I = V*R d) V = I*R

3. The unit of electrical charge is the:

a) Ampere b) Volt c) Coulomb d) Ohm

4. In a DC circuit, the opposition to current flow is called __________, while in an AC circuit it is called __________.

a) Impedance, Resistance b) Resistance, Impedance c) Conductance, Admittance d) Admittance, Conductance

5. What does a capacitor store?

a) Electrical energy in a magnetic field b) Electrical energy in an electric field c) Current d) Voltage

6. The unit of capacitance is the:

a) Henry b) Farad c) Ohm d) Siemens

7. An inductor stores energy in a:

a) Electric field b) Magnetic field c) Gravitational field d) Resistive field

8. The unit of inductance is the:

a) Farad b) Weber c) Henry d) Tesla

9. Which of the following materials is a semiconductor?

a) Copper b) Silicon c) Glass d) Aluminum

10. The flow of electrons is defined as:

a) Voltage b) Current c) Resistance d) Power

11. In a series circuit, the total resistance is:

a) The sum of all individual resistances b) The reciprocal of the sum of the reciprocals of individual resistances c) The average of all individual resistances d) Always less than the smallest resistance

12. In a parallel circuit, which of the following remains the same across all components?

a) Current b) Resistance c) Voltage d) Power

13. According to Kirchhoff's Current Law (KCL), the algebraic sum of currents __________ a junction is zero.

a) Entering b) Leaving c) Both entering and leaving d) Passing through

14. According to Kirchhoff's Voltage Law (KVL), the algebraic sum of all voltages in a closed loop is:

a) Equal to the source voltage b) Zero c) Infinite d) Dependent on the number of resistors

15. If three 15Ω resistors are connected in parallel, the total resistance is:

a) 45Ω b) 15Ω c) 5Ω d) 1.5Ω

16. A circuit has a 12V source and a total resistance of 100Ω. The total current flowing is:

a) 12 A b) 1.2 A c) 0.12 A d) 0.012 A

17. The power dissipated by a resistor can be calculated using the formula:

a) P = V/I b) P = I/R c) P = V * I d) P = I * R^2

18. A wheatstone bridge is used to measure an unknown:

a) Voltage b) Current c) Resistance d) Frequency

19. The standard frequency of AC power in India is:

a) 60 Hz b) 50 Hz c) 100 Hz d) 120 Hz

20. The RMS (Root Mean Square) value of a sinusoidal AC voltage is related to its peak value (Vp) by:

a) V_rms = Vp / 2 b) V_rms = Vp c) V_rms = Vp / √2 d) V_rms = Vp * √2

21. In a purely capacitive AC circuit, the current:

a) Leads the voltage by 90 degrees b) Lags the voltage by 90 degrees c) Is in phase with the voltage d) Leads the voltage by 45 degrees

22. In a purely inductive AC circuit, the current:

a) Leads the voltage by 90 degrees b) Lags the voltage by 90 degrees c) Is in phase with the voltage d) Lags the voltage by 45 degrees

23. The power factor of a purely resistive circuit is:

a) 0 b) 1 c) 0.5 d) -1

24. Impedance in an AC circuit is represented by the letter:

a) R b) X c) Z d) Y

25. A transformer works on the principle of:

a) Mutual inductance b) Self-inductance c) Static electricity d) Ohm's law

26. A step-down transformer:

a) Increases voltage and decreases current b) Decreases voltage and increases current c) Decreases both voltage and current d) Increases both voltage and current

27. A diode is a device that allows current to flow in:

a) Both directions b) Only one direction c) Only when heated d) Only in an AC circuit

28. The forward voltage drop across a standard silicon diode is approximately:

a) 0.3 V b) 0.7 V c) 1.2 V d) 5 V

29. A device used to convert AC to DC is called a:

a) Inverter b) Rectifier c) Oscillator d) Amplifier

30. A Zener diode is primarily used for:

a) Amplification b) Rectification c) Voltage regulation d) Oscillation

31. A transistor (BJT) has how many terminals?

a) 2 b) 3 c) 4 d) 1

32. An LED (Light Emitting Diode) converts electrical energy into:

a) Heat energy b) Light energy c) Sound energy d) Mechanical energy

33. An SCR (Silicon Controlled Rectifier) is a type of:

a) Diode b) Transistor c) Thyristor d) Resistor

34. A multimeter can be used to measure:

a) Voltage and current only b) Voltage, current, and resistance c) Resistance and capacitance only d) Only temperature

35. To measure the current in a circuit, an ammeter should be connected in:

a) Series with the load b) Parallel with the load c) Series with the voltage source d) Parallel with the voltage source

36. To measure the voltage across a component, a voltmeter should be connected in:

a) Series with the component b) Parallel with the component c) Series with the power supply d) Any of the above

37. A transducer is a device that converts:

a) AC to DC b) One form of energy to another c) High voltage to low voltage d) Electrical signals to visual display

38. A thermocouple is a sensor used to measure:

a) Pressure b) Flow c) Level d) Temperature

39. A strain gauge's resistance changes in response to:

a) Temperature change b) Light intensity c) Applied force or strain d) Humidity

40. A 4-20 mA current loop is commonly used in industrial instrumentation because it is:

a) Less susceptible to noise than voltage signals b) Easier to troubleshoot c) Capable of powering the sensor d) All of the above

41. An oscilloscope is used to display:

a) A steady DC voltage value b) The resistance of a component c) A signal's waveform with respect to time d) The total power consumed by a circuit

42. The term "calibration" in instrumentation refers to:

a) Repairing a faulty instrument b) Comparing an instrument's readings to a known standard c) Designing a new instrument d) Replacing an old instrument with a new one

43. A P&ID in instrumentation stands for:

a) Process and Instrumentation Diagram b) Piping and Instrumentation Diagram c) Pressure and Instrument Device d) Power and Induction Diagram

44. A signal conditioner is used to:

a) Generate a new signal b) Amplify, filter, or otherwise modify a sensor's output signal c) Display the signal on a screen d) Convert the signal to a pneumatic output

45. Which of the following is a common type of pressure sensor?

a) Thermistor b) Orifice plate c) Diaphragm d) pH probe

46. The purpose of a fuse in an electrical circuit is to:

a) Increase the current b) Decrease the voltage c) Protect the circuit from overcurrent d) Regulate the voltage

47. A "short circuit" has a resistance of approximately:

a) Infinity b) 1000 Ohms c) 1 Ohm d) Zero

48. An "open circuit" has a resistance of approximately:

a) Zero b) 1 Ohm c) 100 Ohms d) Infinity

49. What type of motor is commonly found in small fans and pumps and runs on a single-phase AC supply?

a) DC motor b) Induction motor c) Stepper motor d) Servo motor

50. The function of a relay is to:

a) Amplify a signal b) Store electrical charge c) Switch a high-power circuit using a low-power signal d) Measure resistance

Top 50 MCQs : Basic Electrical Engineering for Instrument Technicians Quiz

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