Introduction to Electrical Engineering MCQs (Part-11)
What causes electric current to flow in a conductor?
A Resistance
B Current
C Power
D Voltage
Electric current flows in a conductor due to a difference in electric potential, or voltage. Voltage creates an electric field that pushes electrons through the conductor, resulting in a current flow.
What is the effect of increasing resistance in a circuit?
A Increases voltage
B Increases current
C Decreases current
D Decreases power
Increasing resistance in a circuit reduces the current, assuming the voltage remains constant. According to Ohm’s Law, current is inversely proportional to resistance, so a higher resistance leads to lower current.
What is the total resistance in a series circuit?
A Sum of individual resistances
B None of the above
C Product of individual resistances
D Average of resistances
In a series circuit, the total resistance is the sum of the individual resistances. This means that the more resistors you add in series, the higher the total resistance becomes, which reduces the current.
How does current behave in a parallel circuit?
A Current is the same everywhere
B Current is divided among branches
C Current increases with each branch
D Same current through each branch
In a parallel circuit, the current is divided among the branches. The total current is the sum of the currents through each branch, with each branch receiving a portion of the total current based on its resistance.
What does a resistor do in a circuit?
A Store energy
B Control voltage
C Control current
D Convert energy to light
A resistor controls the flow of electric current in a circuit. It offers resistance to the flow of electrons, which reduces the current according to Ohm’s Law, helping to protect components from excessive current.
Which of these is used to measure the resistance of a component?
A Voltmeter
B Wattmeter
C Ammeter
D Ohmmeter
An ohmmeter is used to measure the resistance of a component in a circuit. It measures how much a component resists the flow of current, which is expressed in ohms (Ω).
How is the power consumed in a circuit calculated?
A Power = Voltage / Current
B Power = Voltage × Current
C Power = Current × Resistance
D Power = Voltage × Resistance
Power consumed in a circuit is calculated using the formula P = V × I, where V is voltage and I is current. This gives the rate at which energy is consumed.
What happens to the current if the voltage is doubled in a circuit with constant resistance?
A Quadruples
B Halves
C Doubles
D Stays the same
According to Ohm’s Law (I = V/R), if the voltage is doubled and resistance remains constant, the current will also double. This is because current is directly proportional to voltage in a circuit.
What is the primary function of a capacitor in a circuit?
A Store energy
B Control resistance
C Measure current
D Convert energy to light
A capacitor stores electrical energy in the form of an electric field between its plates. It can release this energy when needed, making it useful for smoothing power supplies, filtering signals, and storing energy temporarily in circuits.
What is the effect of a short circuit?
A Decreases current
B Increases resistance
C Increases voltage
D Causes a large current flow
A short circuit occurs when a low-resistance path is created, allowing a large amount of current to flow through the circuit. This can cause overheating, component damage, and potential fire hazards, which is why circuit breakers are used to prevent it.
What is the SI unit of electric charge?
A Ohm
B Coulomb
C Ampere
D Volt
The SI unit of electric charge is the Coulomb (C). One Coulomb is the charge transported by a current of one ampere in one second. It is a fundamental unit in electromagnetism and electrical engineering.
What does Kirchhoff’s Voltage Law state?
A Voltage is proportional to resistance
B Current is divided equally
C Voltage sum in a loop is zero
D Current is constant
Kirchhoff’s Voltage Law (KVL) states that the sum of all voltages around a closed loop in a circuit must equal zero. This ensures that energy is conserved within the system and is used to analyze complex circuits.
What is the primary cause of energy loss in electrical transmission lines?
A Power
B Voltage
C Resistance
D Current
Energy loss in electrical transmission lines is primarily caused by resistance. As current flows through the conductors, some energy is lost as heat due to the resistance of the wires, resulting in inefficiency in power delivery.
What happens to the total resistance in a parallel circuit if more resistors are added?
A Remains constant
B Decreases
C Doubles
D 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 the reciprocals of each individual resistance. Adding more parallel paths reduces the overall resistance.
What is the function of an ammeter in a circuit?
A Measure current
B Measure resistance
C Measure voltage
D Measure power
An ammeter is used to measure the current flowing through a circuit. It is connected in series with the load to ensure that the current passing through the circuit is accurately measured without affecting the current flow.