Which of the following is the correct SI unit for power?

• A. $J$ (joule)
• B. $W$ (watt)
• C. $V$ (volt)
• D. $N$ (newton)

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the definition of power in physics. Power is the rate at which work is done or energy is transferred over time.
2. Step 2: Recall the formula for power: \(P = \frac{W}{t}\), where \(P\) is power, \(W\) is work done (or energy transferred), and \(t\) is time.
3. Step 3: Identify the SI units for work and time. Work is measured in joules (J), and time is measured in seconds (s).
4. Step 4: Substitute the units into the power formula to find the unit of power: \(\text{unit of } P = \frac{\text{joule (J)}}{\text{second (s)}}\).
5. Step 5: Recognize that the unit joule per second (J/s) is defined as a watt (W), which is the SI unit for power.