The electromagnetic radiations are in descending order of wavelength in the following sequence:
Correct answer: B. Radio-waves, infra-red waves, visible light rays, X-rays
- A. Infra-red waves, radio waves, X-rays, visible light rays
- B. Radio-waves, infra-red waves, visible light rays, X-rays
- C. Radio waves, visible light rays, infra-red waves, X-rays
- D. X-rays, visible light rays, infra-red wave, Radio-waves
Explanation
Radio-waves (103), infra-red waves (10-5), visible light rays (10-6), X-rays (10-10).
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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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