Units of energy versus power

Steps:

• Identify joule (J) as the SI unit for energy.
• Recall gravitational potential energy formula: mgh, measured in J.
• Note latent heat as total energy absorbed/released during phase change, in J.
• Recognize power as rate of energy transfer, measured in watts (W = J/s).
• Confirm work as force times distance, measured in J.

Why C is correct:

• Power is defined as work per unit time (P = W/t), so its unit is J/s (watts), not J.

Why the others are wrong:

• A: Gravitational potential energy is a form of energy (E_p = mgh), measured in J.
• B: Latent heat represents energy transfer (Q = mL), measured in J.
• D: Work is energy transferred by force (W = Fd), measured in J.

Final answer: C