Question

2.7A 110 V heating element in a stove can boil a standard-size pot of water in 1.2 minutes, consuming a total of 136 kJof energy. Determine the resistance of the heating element andthe current flowing through it.

Answer 1

Resistance of the heating element: 6.4 ohm

Current flow:17.17 amperes

Step-by-step explanation:

First we need to convert from Joules to Watts, in order to do that we need the time in seconds:

`1.2 minutes= 1.2mins (60 seconds)/(1 minute) = 72 seconds`

Then apply the formula:

`E(J)= Watts* t(seconds)\\136000= Watts* 72 seconds`

Clearing watts from the equation:

`watts=(136000)/(72) = 1888.9 w`

Then, we know the input voltaje is 110V, and Watts= Voltage* Current.

`(Watts)/(Voltage) =Current\\\\current=(1888.9)/(110) =17.17 amp`

Finally Voltaje over Current= Resistance, from ohm's law

`(V)/(I) =r=(110)/(17.17) = 6.4 ohms`