- #1
7bear
- 18
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~5 qestions~
1. EM wave can be reflected by metal surface only. Right?
2. SONAR can be reflected by any materials. Right?
3. Diffraction only occur when parallel wavefront(not circular wavefront) passes through the gap. Right?
4. After we use cloth to rub some substances, some are positive charged or negative charged. Why?
5. electric force = electrostatic force?
1. EM wave can be reflected by metal surface only. Right?
2. SONAR can be reflected by any materials. Right?
3. Diffraction only occur when parallel wavefront(not circular wavefront) passes through the gap. Right?
4. After we use cloth to rub some substances, some are positive charged or negative charged. Why?
5. electric force = electrostatic force?