Physics Current Electricity PMDC 2020
PMDC Verified Question 80 of 112
One kilowatt-hour is commonly termed as one commercial unit of electric energy which is equal to
A
\( 3.6 \times 10^5 \text{ J} \)
B
\( 3.6 \times 10^6 \text{ J} \)
C
\( 3.6 \times 10^4 \text{ J} \)
D
\( 3.6 \times 10^3 \text{ J} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( 3.6 \times 10^6 \text{ J} \)
Concept:

The Kilowatt-hour (kWh) is a unit of energy, calculated by multiplying power in kilowatts by time in hours.

Solution:

  • 1 kilowatt = 1000 Watts (Joules/second).


  • 1 hour = 3600 seconds.


  • Energy \( E = P \times t = 1000 \text{ W} \times 3600 \text{ s} = 3,600,000 \text{ Joules} \).


  • In scientific notation, this is \( 3.6 \times 10^6 \text{ J} \) (or 3.6 MegaJoules).


Why other options are incorrect:

  • Opt A, C, D: Feature incorrect magnitudes (powers of 10), failing to account for both the kilo multiplier and the 3600 seconds.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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