A multimeter is a versatile tool used to measure current, voltage, and resistance in electrical circuits. It can function as an ammeter, voltmeter, or ohmmeter, allowing for comprehensive testing and troubleshooting.
What is the total resistance in a series circuit?
A Product of resistances
B Sum of individual resistances
C None of the above
D Reciprocal of resistances
In a series circuit, the total resistance is the sum of the individual resistances. The current passing through each resistor is the same, but the total resistance adds up across each component.
In a parallel circuit, what happens to the total resistance when more resistors are added?
A It decreases
B It is zero
C It stays the same
D It increases
In a parallel circuit, adding more resistors decreases the total resistance. The total resistance is found by taking the reciprocal of the sum of reciprocals of the individual resistances, which reduces the overall resistance.
What is the function of an ammeter in an electrical circuit?
A Measure voltage
B Measure power
C Measure current
D Measure resistance
An ammeter is used to measure the current flowing through a circuit. It is connected in series with the components to ensure the current passes through it. The unit of current is amperes (A).
What is the primary function of a voltmeter?
A Measure current
B Measure voltage
C Measure power
D Measure resistance
A voltmeter is designed to measure the voltage or potential difference across two points in a circuit. It is connected in parallel with the component whose voltage is to be measured. The unit of voltage is volts (V).
Which of the following is used to measure electrical power?
A Wattmeter
B Ammeter
C Ohmmeter
D Voltmeter
A wattmeter measures electrical power in watts. It calculates power by multiplying the voltage and current values in a circuit and is typically used in both AC and DC circuits to measure energy consumption.
What is the effect of adding more resistors in series?
A Voltage increases
B Current increases
C Total current decreases
D Total resistance increases
In a series circuit, the total resistance increases as more resistors are added. The total resistance is the sum of all individual resistances, causing the total opposition to current to rise.
What happens in a short-circuit?
A Voltage decreases
B Current bypasses the load
C Resistance becomes infinite
D Current flows through a load
A short-circuit occurs when current bypasses the load due to a direct connection between conductors, causing a very low resistance path. This can result in excess current flow, potentially damaging the circuit.
What is the main advantage of using a parallel circuit?
A Lower current
B Higher resistance
C Independent components
D Increased voltage
The primary advantage of a parallel circuit is that each component operates independently. If one component fails, others continue to work. Additionally, the voltage across each component is the same in a parallel circuit.
What is the function of a circuit breaker?
A Measure current
B Protect against overloads
C Increase current
D Control voltage
A circuit breaker is a protective device that automatically interrupts the current flow in a circuit when an overload or fault occurs. It can be reset after tripping, unlike a fuse, which needs to be replaced.
What does an open circuit indicate?
A No current flow
B Voltage drop across the load
C Complete current flow
D Current bypasses the load
An open circuit means the path for current flow is incomplete, preventing any current from flowing. This can be due to a switch being turned off or a break in the wiring.
What is the effect of increasing the number of resistors in a parallel circuit?
A Increase in total resistance
B Decrease in voltage
C Decrease in current
D Decrease in total resistance
In a parallel circuit, adding more resistors decreases the total resistance. As more paths are available for current, the overall opposition to current decreases, leading to increased current flow.
Which instrument is used to measure resistance?
A Ammeter
B Ohmmeter
C Wattmeter
D Voltmeter
An ohmmeter is used to measure the resistance of a component or circuit. It applies a small current through the resistor and measures the voltage drop to calculate the resistance in ohms.
Which wiring system uses a common return wire for multiple devices?
A Ring circuit
B Series circuit
C Parallel circuit
D Ring circuit
In a ring circuit, multiple devices are connected in a loop, and a common return wire is used. This system is commonly found in household wiring and allows for efficient use of wires.
What happens to the total current in a series circuit?
A It stays the same
B It increases
C It decreases
D It is zero
In a series circuit, the current remains the same through all components. The same amount of current flows through each resistor, but the total voltage is divided across the components based on their resistances.