Question

Two identical heaters 240 V, 1000 W are connected in series across a supply of 240 V line. The combined power is; a)2000 W b)1000 W c)500 W d)4000 W Please show the steps!!

Answer 1

Answer:

(C) 500 watts

Explanation:

Given :

• Two identical heaters of 240v, 1000W are connected in series across a 240 volts line

To find :

• Combined power

P=v²/r

1000=220²/r

1000r=48, 400

r = 48.4 ohms

Given two such heaters are connected in series

So, Req = 48.4×2

Req = 96.8 ohms

Now we have to find power:

P=220²/96.8

P=48,400/96.8

P=500 Watts

The combined power of the heaters will be equal to 500 watts

Hence (C) is correct

Answer 2

Given ,

Power , p = 1000 W

Voltage , V = 240 V

⇒ r = V² / p

⇒ r = 240*240 / 1000

⇒ r = 48.4 Ω

Now two such heaters are connected in series .

⇒ R(eq) = 2r = 96.8 Ω

Voltage , V = 240

⇒ Power , p = V² / R

⇒ p = 240*240 / 96.8

⇒ p = 500 Watts

So option (c) is correct.