*Question T7D07:
Which of the following measurements are made using a multimeter?*  

*Correct Answer is  C: Voltage and resistance*  

### AI Response: (may contain errors)  

To determine which measurements are made using a multimeter, let's analyze the choices:

1. **Correct Answer: C: Voltage and resistance**
   - A multimeter is a versatile tool primarily used to measure:
     - **Voltage**: The potential difference between two points in a circuit, measured in volts (V).
     - **Resistance**: The opposition to current flow in a circuit, measured in ohms (Ω).
   - Multimeters can also measure current (in amperes), but the question specifically highlights voltage and resistance.

2. **Why the other choices are incorrect:**
   - **A: Signal strength and noise**
     - Signal strength and noise are typically measured using specialized equipment like a spectrum analyzer or a signal strength meter, not a standard multimeter.
   - **B: Impedance and reactance**
     - While a multimeter can measure resistance, it does not directly measure impedance (which includes both resistance and reactance) or reactance (the opposition to AC current due to capacitance or inductance). Impedance measurements usually require an LCR meter or similar device.
   - **D: All these choices are correct**
     - Since choices A and B are incorrect, this option cannot be correct.

3. **Useful formulas or rules of thumb:**
   - For voltage measurement:
     - Use the multimeter in parallel with the component.
   - For resistance measurement:
     - Ensure the circuit is powered off and use the multimeter in series with the component.

In summary, the multimeter is primarily used for measuring voltage and resistance, making option C the correct choice.