Electrical Systems Questions

Question 1

What does the term “short circuit” refer to?
a) A broken wire in a circuit
b) An unintended connection causing excessive current flow
c) A circuit with no load
d) A circuit operating at low voltage

Answer 1

b) An unintended connection causing excessive current flow

Question 2

Which device is used to protect circuits from overcurrent?
a) Capacitor
b) Resistor
c) Circuit breaker
d) Transformer

Answer 2

c) Circuit breaker

Question 3

What is the purpose of a multimeter?
a) Measure mechanical force
b) Test hydraulic pressure
c) Measure electrical properties such as voltage, current, and resistance
d) Align components in a circuit

Answer 3

c) Measure electrical properties such as voltage, current, and resistance

Question 4

What is the difference between AC and DC current?
a) AC flows in one direction; DC alternates direction
b) AC alternates direction; DC flows in one direction
c) AC has higher voltage; DC has lower voltage
d) AC is used in batteries; DC is used in power grids

Answer 4

b) AC alternates direction; DC flows in one direction

Question 5

What is the function of a relay in an electrical circuit?
a) To step up or step down voltage
b) To control a high-current circuit using a low-current signal
c) To store electrical energy
d) To measure electrical resistance

Answer 5

b) To control a high-current circuit using a low-current signal

Question 6

What does a capacitor do in an electrical circuit?
a) Increases resistance
b) Stores electrical energy
c) Reduces current
d) Converts AC to DC

Answer 6

b) Stores electrical energy

Question 7

Which device is used to measure current in a circuit?
a) Voltmeter
b) Ammeter
c) Ohmmeter
d) Oscilloscope

Answer 7

b) Ammeter

Question 8

What is the purpose of a fuse in an electrical circuit?
a) To regulate voltage
b) To store energy
c) To protect against overcurrent
d) To measure resistance

Answer 8

c) To protect against overcurrent

Question 9

What is the function of a step-down transformer?
a) Increase voltage
b) Decrease voltage
c) Increase current
d) Convert AC to DC

Answer 9

b) Decrease voltage

Question 10

What does an open circuit indicate?
a) Current is flowing
b) Voltage is zero
c) There is a break in the circuit
d) Resistance is high

Answer 10

c) There is a break in the circuit

Question 11

What is the purpose of an insulator in an electrical system?
a) To conduct electricity efficiently
b) To prevent electrical current from passing through
c) To increase the resistance in the circuit
d) To measure voltage

Answer 11

b) To prevent electrical current from passing through

Question 12

What does a rectifier do in an electrical circuit?
a) Converts DC to AC
b) Converts AC to DC
c) Stores electrical energy
d) Reduces resistance

Answer 12

b) Converts AC to DC

Question 13

What is the primary purpose of a circuit diagram?
a) To measure electrical resistance
b) To visually represent an electrical system
c) To troubleshoot electrical faults
d) To test voltage in a circuit

Answer 13

b) To visually represent an electrical system

Question 14

What is the unit of electrical resistance?
a) Ampere
b) Volt
c) Ohm
d) Watt

Answer 14

c) Ohm

Question 15

Which component is used to temporarily store electrical energy in a circuit?
a) Resistor
b) Capacitor
c) Inductor
d) Transformer

Answer 15

b) Capacitor

Question 16

What happens to current flow if resistance increases in a circuit?
a) Current decreases
b) Current increases
c) Current stays the same
d) Voltage decreases

Answer 16

a) Current decreases

Question 17

What is the purpose of grounding in an electrical system?
a) To increase voltage
b) To provide a safe path for stray current
c) To reduce resistance in a circuit
d) To measure current flow

Answer 17

b) To provide a safe path for stray current

Question 18

What is a common symptom of an overloaded circuit?
a) Flickering lights
b) Low resistance
c) Decreased current flow
d) Reduced voltage

Answer 18

a) Flickering lights

Question 19

Which tool is used to locate faults in an electrical cable?
a) Insulation tester
b) Cable tracer
c) Clamp meter
d) Oscilloscope

Answer 19

b) Cable tracer

Question 20

What is the function of an inductor in an electrical circuit?
a) To store energy in a magnetic field
b) To reduce resistance
c) To convert AC to DC
d) To step up voltage

Answer 20

a) To store energy in a magnetic field

Question 21

If a circuit has a voltage of 12V and a resistance of 4 ohms, what is the current flowing through the circuit?
a) 2A
b) 3A
c) 4A
d) 6A

Answer 21

b) 3A
(Explanation: Using Ohm’s Law: I = V / R = 12V / 4\u03a9 = 3A)

Question 22

What is the voltage across a circuit with a resistance of 10 ohms and a current of 2A?
a) 5V
b) 10V
c) 20V
d) 50V

Answer 22

c) 20V
(Explanation: V = I \u00d7 R = 2A \u00d7 10\u03a9 = 20V)

Question 23

If a circuit has a current of 5A and a voltage of 15V, what is the resistance in the circuit?
a) 2 ohms
b) 3 ohms
c) 5 ohms
d) 10 ohms

Answer 23

b) 3 ohms
(Explanation: R = V / I = 15V / 5A = 3\u03a9)

Question 24

What happens to the current if the voltage is doubled and the resistance remains constant?
a) The current is halved
b) The current remains the same
c) The current is doubled
d) The current is reduced to zero

Answer 24

c) The current is doubled
(Explanation: According to Ohm’s Law, I = V / R. If V doubles and R remains constant, I will double.)

Question 25

A circuit draws a current of 2A with a power supply of 24V. What is the total power consumed by the circuit?
a) 12W
b) 24W
c) 48W
d) 96W

Answer 25

c) 48W
(Explanation: Power (P) = Voltage (V) \u00d7 Current (I) = 24V \u00d7 2A = 48W)