Which of the following can be used to express energy? Symbols have their usual meanings for the units of physical quantities. (i) Wh (ii) VC (iii) `VAs^2` (iv) `A^2 Oemga s`

Options

A. (i), (ii)
B. (ii), (iii), (iv)
C. (i), (ii), (iv)
D. (i), (ii), (iii), (iv)

Explanation

To determine which of the given options can be used to express energy, we need to analyze each option based on the known formulas and units for energy.

### Step-by-Step Solution:

1. **Understanding Energy Units**:
Energy can be expressed in various units. The most common unit of energy in the electrical context is the Joule (J), which can also be expressed in terms of other units such as Watt-hours (Wh), Volt-coulombs (V·C), and others.

2. **Analyzing Each Option**:
- **Option (i): Wh (Watt-hour)**:
- 1 Watt = 1 Joule/second
- Therefore, 1 Watt-hour = 1 Joule/second × 3600 seconds = 3600 Joules.
- This is a valid unit for energy.

- **Option (ii): VC (Volt-coulomb)**:
- 1 Volt = 1 Joule/Coulomb
- Therefore, 1 Volt-coulomb = 1 Joule.
- This is also a valid unit for energy.

- **Option (iii): VAs² (Volt-ampere-seconds squared)**:
- 1 Volt = 1 Joule/Coulomb and 1 Ampere = 1 Coulomb/second.
- Thus, VAs² = (J/C) × (C/s)² = J × C/s² = J × (C/s) × (C/s) = J × (A) × (A) = J·A².
- This does not simplify to a unit of energy. Therefore, it is not a valid unit for energy.

- **Option (iv): A²Ωs (Ampere squared-ohm-seconds)**:
- Using the formula for electrical energy: Energy (E) = I²R·t, where I is current (in Amperes), R is resistance (in Ohms), and t is time (in seconds).
- Thus, E = A² × Ω × s, which is indeed a valid unit for energy.

3. **Conclusion**:
The valid options that can express energy are:
- (i) Wh
- (ii) VC
- (iv) A²Ωs

### Final Answer:
The options that can be used to express energy are (i) Wh, (ii) VC, and (iv) A²Ωs.