Formula to prove speed of electromagnetic wave is equal to speed of light is:
Correct answer: B. B
- A. A
- B. B
- C. C
- D. D
Explanation
Light is an electromagnetic wave: this was realized byMaxwell circa 1864, as soon as the equation c = 1/(e0m0)1/2 = 2.998 X 108m/s was discovered, since the speed of light had been accurately measured by then, and its agreement with c was not likely to be a coincidence.
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About Alternating Current
Alternating current varies periodically, so phase relationships become essential when current passes through a resistor, capacitor or inductor. The chapter distinguishes resistance from capacitive and inductive reactance, explains phase lead and lag, and connects changing electric and magnetic fields with the production and properties of electromagnetic waves.
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