Find the applied voltage when the current is 30 A and the resistance is [tex]$4 \Omega$[/tex].

Select one:
A. [tex]$30 \Omega$[/tex]
B. [tex]$60 \Omega$[/tex]
C. [tex]$120 \Omega$[/tex]
D. [tex]$180 \Omega$[/tex]

Ohm's Law states that voltage equals current times resistance: V = I × R .
Substitute the given values: I = 30 A and R = 4Ω .
Calculate the voltage: V = 30 A × 4Ω = 120 V .
The applied voltage is 120 V ​ .

Explanation

Understanding the Problem We are given the current and the resistance in a circuit and asked to find the voltage. This is a straightforward application of Ohm's Law.

Applying Ohm's Law Ohm's Law states that the voltage (V) across a resistor is equal to the current (I) flowing through it times the resistance (R) of the resistor. Mathematically, this is expressed as: V = I × R

Calculating the Voltage We are given that the current I = 30 A and the resistance R = 4Ω . Substituting these values into Ohm's Law, we get: V = 30 A × 4Ω = 120 V

Final Answer Therefore, the applied voltage is 120 V. The correct answer is c. 120Ω


Examples
Ohm's Law is fundamental in electrical engineering and is used in many real-world applications. For example, when designing a simple circuit to power an LED, you need to choose a resistor that will limit the current to a safe level for the LED. Knowing the voltage of your power source (e.g., a battery) and the desired current for the LED, you can use Ohm's Law to calculate the necessary resistance. This ensures the LED operates correctly and doesn't burn out. Similarly, electricians use Ohm's Law to troubleshoot electrical problems in homes and buildings, such as determining if a circuit is overloaded or if there is a short circuit.

Answered by GinnyAnswer | 2025-07-08

Using Ohm's Law, the applied voltage is calculated as 120 volts when the current is 30 A and the resistance is 4 Ω. The correct choice is C, 120Ω .
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Answered by Anonymous | 2025-07-16