Electrical energy is transmitted over large distances at high alternating voltages. Which of the following statements is (are) correct?

Options

A. For a given power level, there is a lower current
B. Lower current implies less power loss
C. Transmission lines can be made thinner.
D. It is easy to reduce the voltage at the receiving end using step-down transformers.

Explanation

To solve the question regarding the transmission of electrical energy over large distances at high alternating voltages, we will analyze each statement provided and determine which are correct.

### Step-by-Step Solution:

1. **Understanding Power Transmission**:
- Electrical energy is transmitted at high voltages to reduce power loss during transmission. This is because power loss in transmission lines is proportional to the square of the current (I²R losses).

2. **Analyzing Statement A**:
- **Statement A**: "For a given power level, there is lower current."
- **Explanation**: The formula for power is given by \( P = V \times I \). If the voltage (V) is increased, to maintain the same power (P), the current (I) must decrease. Therefore, this statement is correct.

3. **Analyzing Statement B**:
- **Statement B**: "Lower current implies less power loss."
- **Explanation**: Power loss due to resistance in the wires is given by \( P_{loss} = I^2R \). If the current is lower (as established in Statement A), then the power loss will also be lower. Therefore, this statement is correct.

4. **Analyzing Statement C**:
- **Statement C**: "Transmission lines can be made thinner."
- **Explanation**: Thinner transmission lines would increase the resistance (R) of the wire, which would lead to higher power loss (since \( P_{loss} = I^2R \)). Therefore, this statement is incorrect. Transmission lines are typically made thicker to reduce resistance and minimize power loss.

5. **Analyzing Statement D**:
- **Statement D**: "It is easy to reduce the voltage at the receiving end using a step-down transformer."
- **Explanation**: Step-down transformers are indeed used to reduce high transmission voltages to safer levels for use in homes and businesses. Therefore, this statement is correct.

### Conclusion:
The correct statements are A, B, and D. Thus, the answer is **ABD**.