Resistance and Ohm' s law

What is Resistance?

• The flow of electrons

• Electric potential difference

• A battery

• The ability to reduce the flow of electrons

Answer explanation

Resistance is defined as the ability to reduce the flow of electrons in a circuit. It opposes the movement of electric current, making it the correct choice among the options provided.

What is resistance measured in?

• Ω (Ohms)

• V (Volts)

• A (Amps)

• W (Watts)

Answer explanation

Resistance is measured in Ohms (Ω), which quantifies how much a material opposes the flow of electric current. The other units, Volts (V), Amps (A), and Watts (W), measure voltage, current, and power, respectively.

What is the resistance of a lightbulb that experiences 9 Volts and 3 amps of current?

• 1/3 ohms

• 3 ohms

• 27 ohms

• 9 ohms

Answer explanation

To find the resistance, use Ohm's Law: R = V/I. Here, V = 9 Volts and I = 3 Amps. Thus, R = 9/3 = 3 ohms. Therefore, the resistance of the lightbulb is 3 ohms.

The potential difference across a 5 kΩ is 12 V. Find the current flowing through the resistor

• 60 mA

• 2.4 mA

• 1.7 mA

• 0.998 mA

Answer explanation

Using Ohm's Law (V = IR), we can find the current (I). Rearranging gives I = V/R. Here, V = 12 V and R = 5 kΩ (5000 Ω). Thus, I = 12 V / 5000 Ω = 0.0024 A = 2.4 mA. Therefore, the correct answer is 2.4 mA.

What size resistor would produce a 3 Amp current flow with a 12 Volt battery

• 1 Ohm

• 3 Ohms

• 4 Ohms

• 12 Ohms

Answer explanation

Using Ohm's Law (V = I * R), rearranging gives R = V / I. For a 12 Volt battery and 3 Amp current, R = 12V / 3A = 4 Ohms. Thus, the correct resistor size is 4 Ohms.

Electricity that flows in a closed path is called a

• path

• current

• circuit

• light

Answer explanation

Electricity that flows in a closed path is known as a circuit. This term specifically refers to the complete loop through which electric current can travel, making 'circuit' the correct answer.

What is the Voltage of a circuit that has a resistance of 5 Ω and a current of 2 A?

• 25 V

• 10 V

• 2.5 V

• 0.4 V

Answer explanation

Using Ohm's Law (V = I × R), where V is voltage, I is current, and R is resistance: V = 2 A × 5 Ω = 10 V. Therefore, the correct answer is 10 V.

The mathematical relationship among Voltage, Current, and Resistance

• Faraday's Law

• Tesla's Law

• Edison's Law

• Ohm's Law

Answer explanation

Ohm's Law defines the relationship among Voltage (V), Current (I), and Resistance (R) as V = I × R. This fundamental principle is essential in electrical engineering, making it the correct choice among the options.

If the Voltage stays the same and Resistance is increased, Current will 

• Increase

• Decrease

• Stay the same

• X

Answer explanation

According to Ohm's Law (V = IR), if voltage (V) remains constant and resistance (R) increases, the current (I) must decrease. Therefore, the correct answer is 'Decrease'.

If the battery produced 12.6 Volts what would be the current flow for a 6 Ohm resistor?

• 2.1 Amps

• 2.4 Amps

• 1.71 Amps

• 15 Amps

Answer explanation

Using Ohm's Law (V = I * R), we can find the current (I). Rearranging gives I = V / R. Substituting V = 12.6 Volts and R = 6 Ohms, we get I = 12.6 / 6 = 2.1 Amps, which is the correct answer.