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Q72 (IAS/2004) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Electricity and magnetism

Assertion (A) : In our houses, the current in AC electricity line changes direction 60 times per second. Reason (R) : The frequency of alternating voltage supplied is 60 hertz.

Result
Your answer:  ·  Correct: C
Explanation
In an Alternating Current (AC) system, the current reverses its direction twice during every cycle—once to flow in the positive direction and once for the negative. Frequency (Hertz) represents the number of cycles per second. If the frequency is 60 Hz, as stated in the Reason, the current completes 60 full cycles every second. This means the current actually changes direction 120 times per second (60 cycles × 2 changes/cycle). Since the Assertion claims it changes only 60 times, the Assertion is false, while the Reason is a true statement about the supply frequency.
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