If E = 9 V and I = 3 A, what is the resistance R?

If E = 9 V and I = 3 A, what is the resistance R?

• A. 6 Ω
• B. 3 Ω
• C. 9 Ω
• D. 27 Ω

Answer: (B)

Ohm’s Law links voltage, current, and resistance with V = I × R, so rearranging gives R = V / I. With a voltage of 9 volts and a current of 3 amperes, the resistance is 9 ÷ 3 = 3 ohms. This makes sense because applying 3 A across 3 Ω would produce 9 V (V = I × R = 3 A × 3 Ω). If the resistance were 6 Ω, the current would be 9 V ÷ 6 Ω = 1.5 A; if it were 9 Ω, the current would be 1 A; if it were 27 Ω, the current would be 0.333 A. These show why 3 Ω is the correct match for the given values.

Ohm’s Law links voltage, current, and resistance with V = I × R, so rearranging gives R = V / I.

With a voltage of 9 volts and a current of 3 amperes, the resistance is 9 ÷ 3 = 3 ohms. This makes sense because applying 3 A across 3 Ω would produce 9 V (V = I × R = 3 A × 3 Ω).

If the resistance were 6 Ω, the current would be 9 V ÷ 6 Ω = 1.5 A; if it were 9 Ω, the current would be 1 A; if it were 27 Ω, the current would be 0.333 A. These show why 3 Ω is the correct match for the given values.