Basic Voltage and Current MCQs

Voltage and current are two basic properties which are associated with all electrical circuits and components.

Voltage, also known as electric potential difference, is a fundamental concept in electricity and electronics. It refers to the difference in electric potential between two points in an electrical circuit. Electric potential is a measure of the electric potential energy per unit charge at a specific location. Voltage is typically measured in volts (V) and is represented by the symbol “V.” One volt is defined as the electric potential difference between two points in a conductor when one joule of energy is used to move one coulomb of electric charge between those points.

Current, in the context of electricity, refers to the flow of electric charge through a conductor or a circuit. It is a fundamental concept in physics and is measured in amperes (A), represented by the symbol “I.” Current is caused by the movement of charged particles, typically electrons, in a conductor. When a voltage is applied across a conductor or a circuit, it creates an electric field that exerts a force on the charges, causing them to move. The rate of flow of charge is defined as electric current.

In this article Electrical Engineering XYZ shares, basic Electrical MCQs on voltage and current which are important for everyone studying in electronics and electrical field.

It takes 50 J of  energy to move a 5 C charge from point a to point b, the potential difference between point a and b is

It takes 50 J of  energy to move a 5 C charge from point a to point b, the potential difference between point a and b is:

1. 250 V
2. 10 V
3. 5 V
4. 500 V

Correct answer: 2. 10 V

Explanation: Mathematically, V = W/Q = 50 J/5C = 10 V

Cells/batteries are connected in the parallel configuration to increase

Cells/batteries are connected in the parallel configuration to increase:

1. Current capacity
2. Voltage capacity
3. Both of these
4. None of these

Correct answer: 1. Current capacity

Solar panels provide

Solar panels provide:

1. DC
2. AC
3. Both of these
4. None of these

Correct answer: 1. dc

Explanation: Solar panels provide direct current (DC) electricity.

Solar panels consist of photovoltaic cells that convert sunlight directly into electrical energy. The process by which solar panels generate electricity is based on the photovoltaic effect. When photons from sunlight strike the semiconductor material within the solar cells, they excite electrons, creating a flow of electrons or current. This flow of electrons within the solar panel is in the form of direct current (DC).

Direct current is a type of electric current that flows continuously in a single direction. It is commonly used in low-voltage applications, such as batteries, electronics, and certain appliances. However, most household and commercial electrical systems use alternating current (AC) for power transmission and distribution.

To utilize the DC electricity generated by solar panels in AC-based electrical systems, an inverter is typically used. The inverter converts the DC electricity from the solar panels into alternating current (AC) electricity, which is suitable for powering standard household appliances and feeding into the electrical grid.

1 pound is equal to

1 pound is equal to:

1. 2.224  newtons
2. 4.448 newtons
3. 8.996 newtons
4. 36 newtons

Correct answer: b. 4.448 newtons

Voltage is measured by using

Voltage is measured by using:

1. Ammeter
2. Voltmeter
3. Wattmeter
4. None of these

Correct answer: 2. Voltmeter

Explanation: Voltage is measured using a voltmeter.

A voltmeter is a device specifically designed to measure voltage. It is connected in parallel across the points or components where the voltage is to be measured. Voltmeters are designed to have a high input impedance, which means they draw very little current from the circuit being measured, ensuring minimal interference with the circuit’s operation.

An ammeter, on the other hand, is used to measure current in a circuit. It is connected in series with the component or circuit where the current is to be measured.

A wattmeter is used to measure electrical power, which is the product of voltage and current. It is typically used to measure power in AC circuits. While a wattmeter indirectly measures voltage and current, its primary function is to measure power, not voltage alone.

Therefore, the correct answer to the given MCQ is “Voltmeter” since it is specifically used for measuring voltage.

Conventional current flow from the _____ terminal to ______ terminal

Conventional current flow from the _____ terminal to ______ terminal:

1. negative, positive
2. negative, negative
3. positive, negative
4. positive, positive

Correct answer: 3. positive, negative

Explanation: Conventional current flow from the positive terminal to the negative terminal.

In the context of conventional current flow, it is a historical convention that considers the flow of positive charges as the direction of current. This convention was established before the discovery of the electron, which is the primary charge carrier in most electrical systems.

Based on the conventional current flow convention, electric current is considered to flow from the positive terminal of a power source, such as a battery or power supply, to the negative terminal. This means that the positive terminal is the point of higher potential, and the negative terminal is the point of lower potential.

Therefore, in the given multiple-choice question, the correct answer is “positive, negative.” Conventional current flow is from the positive terminal to the negative terminal. It is important to note that while conventional current flow assumes positive charges as the carrier, in reality, negatively charged electrons are the actual charge carriers in most conductors. However, the conventional current flow convention is still widely used in electrical circuit analysis and notation.

240 coulombs of charge pass through a point for 2 minutes, the current is

240 coulombs of charge pass through a point for 2 minutes, the current is:

1. 120 A
2. 240 A
3. 2 A
4. 480 A

Correct answer: c. 2 A

Explanation: I = Q/t = 240 C / (2 * 60 sec) = 2 A

tesla is a unit for

tesla is a unit for:

1. Magnetic flux
2. Magnetic flux density
3. Capacitance
4. Torque

Correct answer: 2. Magnetic flux density

Practically, the current flowing through a short circuit is

Practically, the current flowing through a short circuit is:

1. Very high
2. Infinite
3. Very low
4. Zero

Correct answer: a. Very high

Explanation: Practically, a short circuit has very small resistance. From Ohm’s law, the current and resistance are inversely related. So a. is the correct option.

Practically, the current flowing through a short circuit is very high.

A short circuit occurs when a low-resistance path is unintentionally created in an electrical circuit, bypassing the normal load or resistance. This path typically has minimal or no resistance, allowing a large amount of current to flow.

When a short circuit occurs, the voltage across the short circuit is typically very low, approaching zero. According to Ohm’s Law (V = I * R), if the resistance is low (close to zero), a small voltage difference will result in a significantly higher current.

Since a short circuit has negligible resistance, it effectively removes the impedance or resistance from the circuit. As a result, the current is not limited by the load or any resistance, and a large amount of current flows through the short circuit. The actual value of the current will depend on the voltage source’s capabilities and the resistance of the conductors involved, but it can be extremely high.

In practice, a short circuit can result in excessive heat, damage to equipment, and even pose a fire hazard. Protective devices, such as fuses or circuit breakers, are installed in electrical systems to detect and interrupt the excessive current caused by a short circuit to prevent damage and ensure safety.

The equipment which detects the electric current is

The equipment which detects the electric current is:

1. Rheostat
2. Potentiometer
3. Galvanometer
4. Alternator

Correct answer: c. Galvanometer