Which of the following do not have any effect when a powerful magnet is kept near it?

Options

A. Microphones
B. Glass tumblers
C. Audio and video tapes
D. All of these

Explanation

To solve the question "Which of the following do not have any effect when a powerful magnet is kept near it?", we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the Options**:
We need to examine the materials listed in the options to determine if they are magnetic or non-magnetic.

2. **Analyze Option 1 - Microphones**:
Microphones contain magnets and magnetic materials. When a powerful magnet is brought near a microphone, it will be affected due to the magnetic components inside. Therefore, microphones will have an effect when a powerful magnet is near.

3. **Analyze Option 2 - Glass Tumbler**:
A glass tumbler is made of glass, which is a non-magnetic material. Non-magnetic materials do not get attracted to magnets. Therefore, a glass tumbler will not be affected by a powerful magnet.

4. **Analyze Option 3 - Audio and Video Tapes**:
Audio and video tapes also contain magnetic materials. When a powerful magnet is brought near them, they will be affected as they rely on magnetic properties for their function.

5. **Conclusion**:
Based on the analysis, the only option that does not have any effect when a powerful magnet is kept near it is the glass tumbler.

### Final Answer:
The correct answer is **Option 2: Glass Tumbler**.

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