What is the main purpose of grounding in electrical systems?
A Measure current
B Prevent electric shock
C Store energy
D Limit voltage
Grounding is used to protect people and equipment from electric shock by providing a safe path for excess current to flow into the earth. It ensures electrical safety, especially during faults like short circuits.
What does an electrical diagram represent?
A The energy used
B The current flow
C The voltage levels
D The components and their connections
An electrical diagram is a visual representation of the electrical components and their interconnections within a circuit. It helps technicians and engineers understand how a system operates and aids in troubleshooting and repairs.
What is the standard color for the live wire in most electrical systems?
A Green
B Yellow
C Red
D Blue
In most electrical systems, the live wire is typically red or brown depending on the region. This wire carries the current to the electrical load, and it must be handled with caution due to its potential danger.
What symbol is used to represent a resistor in an electrical diagram?
A A zig-zag line
B A triangle
C A circle
D A straight line
In electrical diagrams, a resistor is usually represented by a zig-zag line. This is the standardized symbol recognized in circuit diagrams, denoting a component that resists the flow of electric current.
What does a switch in an electrical diagram indicate?
A Power supply
B A break in the circuit
C An increase in voltage
D A ground connection
A switch in an electrical diagram indicates a break in the circuit that can open or close, controlling the flow of current. When closed, the current flows; when open, the current is interrupted.
Which wiring system is commonly used in residential buildings?
A Series circuit
B Ring circuit
C Radial circuit
D Parallel circuit
The radial circuit is commonly used in residential wiring systems. In this system, each appliance or socket is connected directly to the distribution board, ensuring easier installation and better protection in case of faults.
What is the function of an earth leakage circuit breaker (ELCB)?
A Protect from overloads
B Detect earth leakage current
C Control the voltage
D Prevent short circuits
An earth leakage circuit breaker (ELCB) detects any leakage current flowing to the earth. It provides protection against electric shocks by disconnecting the circuit if a leakage is detected, ensuring safety in the system.
Which symbol represents a battery in an electrical diagram?
A Two long parallel lines
B A rectangle
C A circle with a plus sign
D A series of short lines
A battery in an electrical diagram is represented by two long parallel lines of unequal length, with the longer line representing the positive terminal and the shorter line representing the negative terminal.
What is the purpose of a fuse in a wiring system?
A Increase current
B Store electrical energy
C Reduce voltage
D Prevent overloads
A fuse is a safety device designed to protect electrical circuits from overloading. It contains a wire that melts when the current exceeds a safe level, breaking the circuit and preventing damage to electrical components.
What does the symbol of a light bulb indicate in an electrical diagram?
A A motor
B A light-emitting component
C A power source
D A fuse
The symbol for a light bulb in an electrical diagram represents a light-emitting component. It is typically depicted as a circle with a filament inside, indicating a device that produces light when electricity flows through it.
In an electrical circuit diagram, what does a straight line represent?
A A conductor
B A resistor
C A switch
D A power source
A straight line in an electrical diagram represents a conductor, typically a wire that connects components in the circuit. It shows the path through which current flows from one component to another.
Which of the following is the correct symbol for a capacitor?
A A rectangle with a line
B Two circles
C A zig-zag line
D Two parallel lines with a gap
A capacitor in an electrical diagram is represented by two parallel lines with a gap between them. This indicates the two conductive plates of the capacitor, with the dielectric material between them storing electrical energy.
What is the purpose of a distribution board in an electrical system?
A Store energy
B Distribute power to circuits
C Measure voltage
D Protect from surges
A distribution board is used to distribute electrical power to different circuits within a building. It houses circuit breakers or fuses that protect each circuit from overloads, ensuring safe and efficient power distribution.
What does a short-circuit symbol in a diagram represent?
A A connected circuit
B A broken wire
C A direct connection between conductors
D An open circuit
A short circuit symbol represents a direct connection between conductors, bypassing the load in a circuit. This can lead to high currents that could cause damage to components or even fires if not protected.
What does a ground symbol in a circuit diagram indicate?
A Grounding of the circuit
B Neutral wire
C Positive terminal
D Connection to a switch
The ground symbol in a circuit diagram indicates that the component is connected to the ground. Grounding provides a safe path for current to flow into the earth, preventing electrical hazards by protecting against electrical faults.