Pages

Monday, 17 October 2016

Joule's first law (Joule Heating)

From your light house bulb to your electric kettle works by electricity.But one thing to be sure, every electrical appliance create heat.maybe some don't create heat but most do. So why heat create in electrical appliance and what's common in joule's first law. Alright dummies!! we going to find out.

Joule's First Law (A.K.A Joule-Lenz Law) : State that power heating generated by electrical conductor to the product is proportional to the current.

Heat generate most of electrical appliance. In terms of electrical, heat consider as a power loss. Because when the more resistance kicks in some electrical appliance it reduce the efficiency that may cause damaged to it. So how to find the amount of heat generate through a resistance to a conductor. Well lets do some mathematics equation.

Before the equation let see what is power. Power is work done by per minute. Let say you lifting heavy box. When you lift the heavy box, it may take time to lift. While lifting you may feel your body is heating. There's same goes to the conductor. When the conductor experience more resistance like you lift heavy load, it cause heat. So the equation is 
Using this formula you can predict how power is generate in order to create. In. P=IV is used to find how much power is used with current and voltage. Using this P=IV formula, P=I2R and P= V2R. Each formula is find by ohm's law formula V=IR.

For example, your kettle produce 8000 joules of 10 seconds.So find the value of resistance and current. The first thing to find out is the power that kettle produce. You need to use this formula P=Work done/Time. So :
 P= 8000/10
800W.
The kettle produce 800Watts. To find resistance is R=V2/P
R=(240)2/800
 72Ω
To find the current I=P/R
I=800/72
11.1A
  

 

No comments:

Post a Comment