U7: Ohm's Law & Circuits Math Review

Front

What is Ohm's Law?

Back

Ohm's Law states that the current (I) through a conductor between two points is directly proportional to the voltage (V) across the two points and inversely proportional to the resistance (R) of the conductor. It can be expressed as V = I × R.

Front

What is the formula to calculate power in an electrical circuit?

Back

Power (P) can be calculated using the formula P = V × I, where P is power in watts, V is voltage in volts, and I is current in amperes.

Front

How do you calculate the total resistance in a series circuit?

Back

In a series circuit, the total resistance (R_total) is the sum of all individual resistances: R_total = R1 + R2 + R3 + ... + Rn.

Front

How do you calculate the total resistance in a parallel circuit?

Back

In a parallel circuit, the total resistance (R_total) can be calculated using the formula: 1/R_total = 1/R1 + 1/R2 + 1/R3 + ... + 1/Rn.

Front

What is the unit of electrical resistance?

Back

The unit of electrical resistance is the ohm (Ω).

Front

If a toaster has a resistance of 9.2 ohms and operates at 5.5 amps, what is the voltage?

Back

Using Ohm's Law, V = I × R, the voltage is V = 5.5 A × 9.2 Ω = 50.6 V.

Front

What is the current in a circuit with a voltage of 10V and a total resistance of 2.5 ohms?

Back

Using Ohm's Law, I = V / R, the current is I = 10 V / 2.5 Ω = 4 A.

Front

What is the relationship between voltage, current, and resistance?

Back

The relationship is defined by Ohm's Law: V = I × R, meaning voltage is the product of current and resistance.

Front

How much power does a device use if it draws 14.0 amps from a 120 volt circuit?

Back

Using the power formula P = V × I, the power used is P = 120 V × 14.0 A = 1,680 Watts.

Front

What is the current flow if the voltage is 14.5 volts and the resistance is 6 ohms?

Back

Using Ohm's Law, I = V / R, the current is I = 14.5 V / 6 Ω = 2.41 A.