A 100 W bulb operates at 220 V. The current drawn by it is approximately:
A. 0.22 A
B. 0.45 A
C. 4.5 A
D. 2.2 A
Answer: Option B
Solution (By JKSSB Mock Tests)
Electric power P = VI. Thus I = P/V = 100 W / 220 V ≈ 0.4545 A ≈ 0.45 A. This direct application of power formula is fundamental in electricity. Memory tip: 'I = P/V for resistive loads'. Competitive exams frequently test such calculations with household appliance ratings. Always use consistent units (watts, volts, amperes). Note: This assumes purely resistive load (valid for incandescent bulbs); for motors or electronics, power factor may matter, but not at this level.
Explanation:
A rainbow is formed by sunlight interacting with water droplets. As light enters the droplet, it undergoes refraction and dispersion (separating into colors). The light then strikes the back of the droplet and undergoes total internal reflection. Finally, it undergoes a second refraction as it exits, spreading the spectrum out for the observer to see.
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