A meter rod is moving with speed of light with respect to a stationary observer. The length of the rod will appear to the observer as approaching:
Correct answer: B. Zero m
- A. Infinite
- B. Zero m
- C. 2 meter
- D. None of above.
Explanation
Formula for length contraction is L=L0√1−v2/c2, where: • L = new length (m) • L0 = original length (m) • v = speed of object (ms−1) • c = speed of light (~3.00⋅108ms−1) So, L=√1−c2/c2 =√1−1 =√0 L=0 meter
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Quantum theory treats electromagnetic radiation as packets of energy called photons, with energy proportional to frequency through E equals hf. The topic covers Planck's hypothesis, photon momentum, the photoelectric effect, threshold frequency, work function and wave particle duality, distinguishing quantised energy exchange from classical continuous radiation.
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