*Question T5A04:
What are the units of electrical resistance?*  

*Correct Answer is  C: Ohms*  

### AI Response: (may contain errors)  

The correct answer to the question about the units of electrical resistance is **Ohms**.

1. **Why the correct answer is correct:**
   - The unit of electrical resistance is defined as the Ohm (symbol: $\Omega$). It is a measure of how much a material opposes the flow of electric current. According to Ohm's Law, resistance ($R$) can be calculated using the formula:
   $$
   R = \frac{V}{I}
   $$
   where:
   - $V$ = voltage in volts
   - $I$ = current in amperes

2. **Why the other choices are incorrect:**
   - **A: Siemens**: This is the unit of electrical conductance, which is the inverse of resistance. It is defined as:
   $$
   \text{Siemens} = \frac{1}{\text{Ohm}}
   $$
   - **B: Mhos**: This is an older term for Siemens and also represents conductance, not resistance. It is simply the reciprocal of Ohms.
   - **D: Coulombs**: This is the unit of electric charge, not resistance. It measures the quantity of electricity.

3. **Useful formulas or rules of thumb:**
   - Remember Ohm's Law: 
   $$
   V = I \times R
   $$
   - The relationship between resistance ($R$), voltage ($V$), and current ($I$) is fundamental in understanding electrical circuits.

In summary, the unit of electrical resistance is Ohms, while Siemens and Mhos refer to conductance, and Coulombs refer to charge.