Question

An iron box of resistance 100 Ohm work on 240 volt calculate the power of the device
A.570W
B. 24000W
C. .24W
D. 576W

Answer 1

GiveN :

• Resistance (R) = 100 ohm
• Potential Difference (V) = 240 V

To FinD :

• Power of the device

SolutioN :

We are given that resistance and potential difference of a conductor are 100 ohms and 240 Volts respectively. And we have to find power of the device. For this we have to solve question in two steps :

• By using Ohm's Law

• Then formula for Power

______________________

Use Ohm's Law :

⇒V = IR

⇒I = V/R

⇒I = 240/100

⇒I = 2.4

$\therefore$ Current flowing in circuit is 2.4 Ampere.

________________________________

Now, use formula for Power :

⇒P = VI

⇒P = 240 * 2.4

⇒P = 24 * 24

⇒P = 576

$\therefore$ Power of the device is 576 Watts

Answer 2

Given ,

An Iron box has resistance , R = 100 Ω

It works on 240 volt.

Hence , Voltage , V = 240 v

We know that " Power is defined as the product of voltage and current "

$\implies \bold{P=VI}$ ... (1)

But here Current ( I ) is not given.

So use Ohm's law i.e., V = IR

⇒ I = V/R

Now sub. this in (1) , we get ,

$\bold{P=V(\frac{V}{R})}\\\\\implies \bold{P=\frac{V^2}{R}}\\\\\implies \bold{P=\frac{240^2}{100} }\\\\\implies \bold{Power,P=576\ watts}$

So the power of the device is 576 watts