What is the resistance of a circuit in which a current of 3 amperes flows when connected to 90 volts?

• A. 45 ohms
• B. 30 ohms
• C. 27 ohms
• D. 90 ohms

Answer: (B)

To determine the resistance of a circuit, you can use Ohm's Law, which states that voltage (V) equals current (I) times resistance (R). This can be expressed with the formula:

[ R = \frac{V}{I} ]

In this scenario, the voltage is 90 volts and the current is 3 amperes. By substituting these values into the formula, we perform the calculation:

[ R = \frac{90 \text{ volts}}{3 \text{ amperes}} = 30 \text{ ohms} ]

Therefore, the resistance of the circuit is 30 ohms. This calculation clearly shows how the relationship defined by Ohm's Law allows us to find resistance based on provided values of voltage and current. Understanding this formula is crucial for anyone studying electronics and radio communications, as it applies to many practical situations in electrical engineering and ham radio operations.