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Q76 (NDA-II/2009) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Electricity and magnetism Answer Verified

i house, served by a 220 V supply line, is protected y a 9A fuse. What is the maximum number of 60 ratt bulbs that can be turned on in parallel?

Result
Your answer: —  Â·  Correct: C
Explanation

To find the maximum number of bulbs, we first calculate the total power capacity of the circuit using the formula P = V × I. With a supply voltage of 220 V and a fuse rating of 9 A, the maximum allowable power is 1980 W (220 V × 9 A) [t2][t3]. Each bulb is rated at 60 W. Since the bulbs are connected in parallel, the total power consumed is the sum of the power of each bulb [t6]. By dividing the total power capacity (1980 W) by the power of a single bulb (60 W), we get 33 bulbs [t2][t3][t8]. Alternatively, one can calculate the current drawn by a single bulb (I = P/V), which is approximately 0.2727 A [t10]. Dividing the total fuse current (9 A) by the current per bulb (0.2727 A) also yields 33 bulbs [t2][t5]. Thus, 33 bulbs can be safely operated without blowing the fuse.

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