Question

a number of bulbs of the same power and voltage rating 100W-220V are used in parallel for 4 hours at 250 V .If the energy consumed is 2.5KWh,find the number of bulbs​

Answer 1

Answer:

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Explanation:

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Answer 2

The number of bulbs​ is 160

Given:

1. Power rating of each bulb = 100W
2. Voltage rating of each bulb = 220V
3. Applied voltage = 250V
4. Time = 4 hours
5. Energy consumed = 2.5KWh

To find:

1. Number of bulbs

Answer:

• Let the number of bulbs be n
• We know that for a series connection of bulbs,
• Vseries = V1 + V2 + ....  +Vn
• 1/Pseries = 1/P1 + 1/P2 + ....  +1/Pn
• Vseries =220n
• Pseries = 100/n
• P = V * I

• I = P/V
• I = (100/n) / 220n
• I = 10/(22n²)
• Now, Energy E = 2.5KWh
• E = P * t

• 2.5 = ( 100/n )* 4

• n = 400/ 2.5
• n = 160