Which of the following is correct about microwave oven?

Options

A. Energy produced by the microwave oven is efficiently transferrred to the kinetic energy of water molecules at resonance
B. The frequency of rotation of water molecules is 3GHz.
C. We should not use metla containers in a miecrowave oven because of getting shock from accumulated electric charges.
D. All of these

Answer

To solve the question regarding the correct statements about microwave ovens, we can analyze the information provided step by step.

### Step-by-Step Solution:

1. **Understanding Microwave Ovens**:
- A microwave oven is an electric appliance that heats and cooks food using electromagnetic radiation in the microwave frequency range.

**Hint**: Remember that microwaves are a type of electromagnetic radiation.

2. **Frequency of Water Molecules**:
- The frequency of rotation of water molecules is approximately 3 gigahertz. This frequency corresponds to the microwave frequency range, which is why microwaves are effective in heating food.

**Hint**: Consider how the frequency of microwaves interacts with water molecules.

3. **Energy Transfer at Resonance**:
- The energy produced by the microwave oven is efficiently transferred to the kinetic energy of water molecules when the frequency of the microwave matches the natural frequency of the water molecules. This condition is known as resonance.

**Hint**: Think about how resonance enhances energy transfer.

4. **Using Metal Containers**:
- It is advised not to use metal containers in a microwave oven. When metal is present, it can accumulate electric charges due to the microwave radiation. This can lead to electric shocks when the container is touched.

**Hint**: Reflect on the properties of metals in electromagnetic fields.

5. **Conclusion**:
- Based on the analysis, all the statements regarding microwave ovens are correct. Therefore, the best answer is that all options are correct.

### Final Answer:
The correct option is that all of the statements about microwave ovens are correct (Option 4).