Question

calculate the time taken for an electric iron with resistance 20 ohms to produce 15,000 j of heat if it draws 5a of current.​

Answer 1

Given :-

Resistance of the iron = 20 ohm          

Current = 5 ampere          

Time = 30 seconds  

To Find :-

Heat Produced.

Formula to be used :-

Heat produced = I²RT    

Solution :-

Putting all the values, we get    

Heat produced = I²RT          

Heat produced = 25 × 20 × 30          

Heat produced = 15000 Joules.

Hence, the heat produced in 30 seconds is 15000 Joules.

Extra Information :-

One Volt Potential Difference - The potential difference between two points in an electric field is the amount of work done in bringing a unit positive charge from one point to another.

Potential Difference = Work done/Charge = W/Q

Answer 2

$\huge{\fbox{\fbox{\sf{\blue{Given\: :-}}}}}$

Resistance, R = 20 ohm

Heat, H = 15000 J

Current, I = 5 A

$\huge{\fbox{\fbox{\sf{\blue{Solution\: :-}}}}}$

We know,

H = I² × R × T

⟹ 15000 J = 5 A × 5 A × 20 ohm × T

⟹ 15000 = 500 T

$\sf{\implies\: T\: =\: {\dfrac{15000}{500}}}$

⟹ T = 30

∴ The iron takes 30 seconds of time.