Ohm's Law and Circuits

What is the formula for Ohm's Law?

• I = V / R

• I = R / V

• I = V * R

• I = V + R

Answer explanation

The correct formula for Ohm's Law is I = V / R, where I represents current, V represents voltage, and R represents resistance.

How do you calculate resistance in a circuit?

• R = P / V

• R = V / I

• R = I / V

• R = V * I

Answer explanation

To calculate resistance in a circuit, you use the formula R = V / I, where R is resistance, V is voltage, and I is current. This formula represents Ohm's Law.

Describe the relationship between voltage and current in a circuit.

• Voltage and current are inversely proportional in a circuit.

• Voltage and current are unrelated in a circuit.

• Voltage has no effect on current in a circuit.

• Voltage and current are directly proportional in a circuit.

Answer explanation

Voltage and current are directly proportional in a circuit, meaning an increase in voltage leads to a proportional increase in current.

Maya is working on her science project about electricity and needs to analyze a series circuit she built with light bulbs. How should she proceed?

• Divide the bulbs resistance by the number of bulbs she has in the circuit.

• Calculate the total resistance by adding the resistance of all the bulbs in the circuit.

• Use Ohm's Law to calculate resistance

• Analyze parallel circuits instead

Answer explanation

Total resistance in a series circuit is the sum of all the resistors.

Hannah and Samuel are working on a science project to create a parallel circuit for their school's science fair. How should they analyze their parallel circuit to ensure it works correctly?

• Calculate total resistance using 1/RT = 1/R1 + 1/R2 + 1/R3 + ..., then use Ohm's Law to find current and voltage

• Analyze each component separately without considering the circuit as a whole

• Calculate total resistance by adding all resistances together

• Use Kirchhoff's Voltage Law to find total voltage

Answer explanation

Calculate total resistance using 1/RT = 1/R1 + 1/R2 + 1/R3 + ..., then use Ohm's Law to find current and voltage

Tags

NGSS.MS-PS2-3

What happens to resistance in a series circuit?

• Decreases

• Stays the same

• Becomes negative

• Increases

Answer explanation

In a series circuit, resistance increases because the total resistance is the sum of individual resistances. Therefore, the overall resistance in a series circuit is higher than the resistance of any individual component.

What happens to voltage in a parallel circuit?

• Voltage decreases

• Voltage fluctuates

• Voltage increases

• Voltage remains the same

Answer explanation

In a parallel circuit, voltage remains the same across all components as they are connected directly across the voltage source.

If the current in a circuit is 2A and the resistance is 5 ohms, what is the voltage?

• 7V

• 15V

• 3V

• 10V

Answer explanation

Using Ohm's Law (V = I * R), we can calculate the voltage as V = 2A * 5 ohms = 10V. Therefore, the correct answer is 10V.

In a series circuit with three resistors of 2 ohms each, what is the total resistance?

• 8 ohms

• 4 ohms

• 6 ohms

• 2 ohms

Answer explanation

In a series circuit, total resistance is the sum of individual resistances. Therefore, total resistance = 2 ohms + 2 ohms + 2 ohms = 6 ohms.

If two resistors of 4 ohms each are connected in parallel, what is the total resistance?

• 2 ohms

• 6 ohms

• 5 ohms

• 3 ohms

Answer explanation

When resistors are connected in parallel, the total resistance is calculated using the formula: 1/RT = 1/R1 + 1/R2. Substituting R1 = R2 = 4 ohms, we get RT = 2 ohms.