Understanding Ohm's Law Concepts

Match the following electrical quantities with their relationships according to Ohm's Law.

• Relationship involving power calculation

• Resistance, Power, and Capacitance

• Relationship involving voltage and inductance

• Voltage, Current, and Power

• Relationship involving capacitance and power

• Voltage, Capacitance, and Inductance

• Ohm's Law relationship

• Voltage, Current, and Resistance

Answer explanation

Ohm's Law defines the relationship between Voltage (V), Current (I), and Resistance (R) in an electrical circuit, expressed as V = I × R. Thus, the correct answer is Voltage, Current, and Resistance.

If a circuit has a voltage of 12 volts and a current of 2 amperes, what is the resistance?

• 6 ohms

• 24 ohms

• 0.5 ohms

• 10 ohms

Answer explanation

Using Ohm's Law, resistance (R) can be calculated as R = V/I. Here, V = 12 volts and I = 2 amperes. Thus, R = 12/2 = 6 ohms, which is the correct answer.

What is the formula for Ohm's Law?

Answer explanation

Ohm's Law states that voltage (V) is equal to the current (I) multiplied by the resistance (R). Therefore, the correct formula is V = I × R, which is the first choice.

Match the following descriptions with the correct statement about resistance in a series circuit.

• Method used for calculating equivalent resistance in parallel circuits.

• It is the average of the individual resistances.

• Resistance calculation method not applicable to series circuits.

• It is the product of the individual resistances.

• Resistance calculation for resistors in parallel.

• It is the reciprocal of the sum of the reciprocals of the individual resistances.

• Total resistance in a series circuit.

• It is the sum of the individual resistances.

Answer explanation

In a series circuit, the total resistance is calculated by adding the individual resistances together. Therefore, the correct answer is that the total resistance is the sum of the individual resistances.

The unit of measurement for resistance is (a)  

• Volt
• Ampere
• Ohm
• Watt

Answer explanation

The unit of measurement for resistance is the Ohm. It quantifies how much a material opposes the flow of electric current, making it the correct choice among the options provided.

If a resistor has a resistance of 10 ohms and the current flowing through it is 3 amperes, what is the voltage across the resistor?

• 30 volts

• 3 volts

• 10 volts

• 13 volts

Answer explanation

Using Ohm's Law (V = I × R), where V is voltage, I is current, and R is resistance, we calculate V = 3 A × 10 Ω = 30 volts. Therefore, the voltage across the resistor is 30 volts.

In a parallel circuit, how does the total current compare to the individual branch currents?

• It is the sum of the individual branch currents.

• It is the product of the individual branch currents.

• It is the average of the individual branch currents.

• It is the same as the largest branch current.

Answer explanation

In a parallel circuit, the total current is equal to the sum of the individual branch currents. This means that the total current flowing from the source is distributed among all branches, confirming the correct choice.

What is the power dissipated by a resistor with a resistance of 5 ohms and a current of 2 amperes flowing through it?

• 10 watts

• 20 watts

• 5 watts

• 40 watts

Answer explanation

The power dissipated by a resistor can be calculated using the formula P = I²R. Here, I = 2 A and R = 5 Ω. Thus, P = (2)² * 5 = 4 * 5 = 20 watts. Therefore, the correct answer is 20 watts.

The correct unit for measuring electrical power is (a)  

• Volt
• Ampere
• Ohm
• Watt

Answer explanation

The correct unit for measuring electrical power is the Watt. It quantifies the rate of energy transfer, while Volt measures electric potential, Ampere measures current, and Ohm measures resistance.

If the voltage across a circuit is doubled, what happens to the current, assuming resistance remains constant?

• It doubles.

• It halves.

• It remains the same.

• It quadruples.

Answer explanation

According to Ohm's Law (V = IR), if voltage (V) is doubled and resistance (R) remains constant, current (I) must also double to maintain the equation. Therefore, the correct answer is that the current doubles.