In our house all electric devices operate on 220 V. It implies that

Options

A. they are connected in parallel
B. they are connected in series
C. they all have currents of equal values
D. they all have the same resistance

Answer

To solve the question regarding why all electric devices in a house operate on 220 V, we can analyze the implications of this voltage specification step by step.

### Step-by-Step Solution:

1. **Understanding Voltage in Household Devices**:
- The statement mentions that all electric devices operate on 220 V. This indicates that the voltage supplied to each device is 220 volts.

**Hint**: Recall that voltage is the electrical potential difference that drives current through a circuit.

2. **Types of Connections**:
- Electric devices can be connected in two main configurations: series and parallel.
- In a **series connection**, the same current flows through all devices, but the voltage across each device can vary depending on their resistances.
- In a **parallel connection**, each device is connected directly across the voltage source, meaning each device experiences the same voltage.

**Hint**: Remember the characteristics of series and parallel circuits regarding voltage and current.

3. **Implication of Operating Voltage**:
- Since all devices operate at the same voltage (220 V), it suggests that they must be connected in such a way that they all receive this same voltage.

**Hint**: Think about how devices would be connected to ensure they all receive the same voltage.

4. **Conclusion on Connection Type**:
- The only way to ensure that all devices receive the same voltage of 220 V is if they are connected in parallel. In a parallel circuit, the voltage across each device is equal to the source voltage.

**Hint**: Consider the implications of connecting devices in series versus parallel when it comes to voltage.

5. **Final Answer**:
- Therefore, the correct conclusion is that all electric devices in the house are connected in parallel.

### Final Answer:
**They are connected in parallel.**