Question

....

Two lamps one rated 100W at 220 volt and the other 60W at 220volt are connected in parallel to electric main supply . What current is draw from the line if the supply voltage is 220 V ?

Answer 1

_________Heyy Buddy ❤_________

_______Here's your Answer __________

Given :-

For the 1st Lamp.

Power = 100 Watt

Voltage = 220 V.

Now,

$p = \frac{ {v}^{2} }{r} \\ \\ = > 100 = \frac{220 \times 220}{r} \\ \\ = > r = \frac{220 \times 220}{100} \\ \\ = > r = 22 \times 22 \\ \\ = > r = 484 \: ohm$

☆ For the second lamp

Given:-

Power = 60 W.

Voltage = 220V.

Now,

$p = \frac{ {v}^{2} }{r} \\ \\ = > 60 = \frac{ {220}^{2} }{r} \\ \\ = > r = \frac{220 \times 220}{60} \\ \\ = > r = 806.7 \: ohm$

Since,

Both the resistor are connected in parallel.

Therefore,

$\frac{1}{r} = \frac{1}{r1} + \frac{1}{r2} \\ \\ = > \frac{1}{r} = \frac{1}{484} + \frac{1}{806.7} \\ \\ by \: taking \: l.c.m. \: \: we \: get \\ \\ = > \frac{1}{r} = \frac{806.7 + 484}{806.7 \times 484} \\ \\ = > \frac{1}{r} = \frac{1290.7}{390442.8} \\ \\ = > r = \frac{390442.8}{1290.7} \\ \\ = > r = 302.5 \: ohm.$

Now, For Current,

Given:-

V = 220

R = 302.5

So,

V = I × R

=> 220 = I × 302.5

=> I = 220/302.5

=> I = 0.73 Ampere.

So, The Current drawn is 0.73 Ampere.
✔✔✔✔