Which does not have the same unit as others?

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Accepted Answer

1. **Analyze Option A (Watt-sec):** Power ($P$) is defined as Work/Time ($W/t$). Therefore, Work/Energy = Power $	imes$ Time. Watt-second is a unit of **Energy** ($1 	ext{ W s} = 1 	ext{ J}$). 
2. **Analyze Option B (Kilowatt-hour):** This is a commercial unit of **Energy**, commonly used for electricity. $1 	ext{ kWh} = 3.6 	imes 10^6 	ext{ J}$ .
3. **Analyze Option C (eV):** The electron volt (eV) is a unit of **Energy** used in atomic and nuclear physics. $1 	ext{ eV} \approx 1.60 	imes 10^{-19} 	ext{ J}$ .
4. **Analyze Option D (J-sec):** Joule-second is the unit of Planck's constant ($h$) . It represents Energy $	imes$ Time (Dimensions: $[ML^2T^{-1}]$), which corresponds to Angular Momentum, not Energy.
5. **Conclusion:** Watt-sec, Kilowatt-hour, and eV are all units of Energy. J-sec is a unit of Action or Angular Momentum.

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