- #1
zwarrior
- 10
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Hello all. I want to do some experiment but I thought I would go over this theoretically before trying out and now I have a doubt.
I know this is a big question and difficult to answer here. But any small help is appreciated as I am confused with this.
Homework Statement
- I have a driver which produces say 600mA. I connect the driver to one end of Nichrome Wire. And the other end of Nichrome wire is in contact with A Mild Steel substance.
- I want to know (my main doubts are) (a)-How much heat is generated in the Nichrome Wire due to the current in 1 second? (b) For 1 second, what will be the change in temperature at the mild steel due to the current produced by driver? (Assuming initial temperature= the room temperature .i.e 24C).
Homework Equations
- Joules law= H=(I^2)*R*t
- Specific Heat Capacity= Q=cp*m*dT
- time required to change temperature of object=t=(m*cp*dT)/H
The Attempt at a Solution
- By Joules's law of heating, H=(I^2)*R * t. where I=600 mA, R of Nichrome wire is 2.196 ohms. Therefore heat emitted by Nichrome wire is H=0.79J for 1 second. DOUBTS - Is 0.79J of heat is there in the Nichrome wire in 1 second. And does it mean the heat present in Nichrome wire for 2 seconds is 0.79*2 ?
- Temperature change in Nichrome wire dT= (h*t)/(Cp*m); where H=0.79J(from above answer);t=1 sec;Cp=specific heat capacity of nichrome=0.45 J/gC; mass=10 g. After evaluating, I get dT=0.175 C. So, for 1 second, temperature of Nichrome rises by 0.175 C ?
- Now, I need temperature change in mild steel for one second. So, I used this formula, Time required to change temperature of mild steel=(m*Cp*dt)/H. H=0.79J (from point-1) Here, mass of mild steel=5 g; dt=0.175 C (from above answer); Specific heat capacity of mild steel= 0.51 J/gC. After evaluating, I get t=0.56 seconds. This means, for 0.5 seconds, temperature in steel changes by amount of 0.175 C. So, I need 3.36 seconds for 1 C change.
I know this is a big question and difficult to answer here. But any small help is appreciated as I am confused with this.
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