The root mean square value of alternating current is defined as the equivalent DC current that produces the same:
A. Power dissipation
B. Voltage
C. Charge flow
D. Magnetic field
Answer: Option A
Solution (By JKSSB Mock Tests)
RMS value of AC is defined such that I_rms²R = average power dissipated, same as DC current I_dc would produce (I_dc²R). Thus I_rms = I₀/√2 for sinusoidal AC. This definition ensures power calculations use RMS values. Memory tip: 'RMS: heating effect equivalent to DC; I_rms = 0.707 I₀ for sine wave'. This AC fundamentals concept is frequently tested in competitive exams. Always use RMS values for power calculations in AC circuits; peak values overestimate power.
Explanation:
The thermal efficiency (η) of a reversible Carnot engine depends exclusively on the absolute temperatures of the hot source (T1) and the cold sink (T2). The formula is η = 1 - (T2/T1), or (T1 - T2) / T1. Temperatures must be in Kelvin. It shows no engine can be 100% efficient unless the sink is at absolute zero.
Explanation:
Inertia is directly proportional to mass. Heavier object harder to accelerate/decelerate. Newton's first law defines inertia. Momentum is mass × velocity, depends on motion.
Explanation:
Fuse melts and breaks circuit when current exceeds rating. MCB (Miniature Circuit Breaker) does same but resettable. Switch only turns on/off. Resistor limits current but doesn't break.
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