Building a water heater- using battery and wire

In summary, a 6 volt battery and 10^-6 ohms/meter Nichrome wire was used to create a water heater that can heat water from 20 degrees Celsius to 40 degrees Celsius in 60 seconds.
  • #1
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Homework Statement


Need to heat 30mL of water from 20C to 40C in 1 min(60s).
Using 6V battery and Nickel Chromium alloy Nichrome wire that has a resistivityabout 10^-6 ohms/meter. So you use the battery and the wire to build a water heater.
Batter has no internal resistance.


Homework Equations


1How much heat energy in joules needed?
2How much power do you need to do it in the time indicated?
3What resistance should your nichrome coil have in order to produce this much power in heat?
4Can you create a coil from the wire having these perperties? (length needed)
5If the internal resistance of the battery were1/3 ohms, how would it effect your calculation?
(only explain what you have to do, don't recalculate the size of your coil)


The Attempt at a Solution


1:mc(delta)=2508J
2:total joules/time(60s) =41.8W
3:R=v/I = 0.8587 ohms
4: R needed divide by the resistance of the wire, so 857142 m
5: I don't get this part but I think that a longer time will be required?

I think the length of the wire I calculated is probably wrong, but I don't know which step I did wrong, so please help, thanks =p
 
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  • #2
Your calcs look good to me, but this "resistivity about 10^-6 ohms/meter" is unreasonable - better check that number! Looks like gold wire rather than nichrome.
 
  • #3
What units have you used in the first step? I got smaller amount of energy needed. And my guess would also be, that the unit of resistivity is wrong. Usually it's ohm*meter, not ohm/meter.
 
  • #4
Kruum said:
Usually it's ohm*meter, not ohm/meter.
Bulk resistivity is ohm-meter, but for wire of a given CSA you can quote Ohm/meter
 
  • #5
mgb_phys said:
Bulk resistivity is ohm-meter, but for wire of a given CSA you can quote Ohm/meter

Okay. Thanks for correcting.
 
  • #6
thanks everyone
I was just unsure about the length of the wire I got
but I get it now =P
 

Related to Building a water heater- using battery and wire

1. How does a water heater using battery and wire work?

A water heater using battery and wire works by using a battery as a power source to heat a wire coil, which then heats the water in the tank. The battery creates an electrical current that flows through the wire, producing heat through resistance. This heat is then transferred to the water, heating it up.

2. What type of battery is needed for a water heater using battery and wire?

The type of battery needed for a water heater using battery and wire depends on the size and power requirements of the heater. Generally, a deep cycle marine battery or a 12-volt car battery can be used for this purpose.

3. How long does it take for the water to heat up with a water heater using battery and wire?

The time it takes for the water to heat up with a water heater using battery and wire depends on several factors such as the size and power of the battery, the capacity of the water tank, and the starting temperature of the water. On average, it can take anywhere from 20-60 minutes for the water to reach a desired temperature.

4. Is it safe to use a water heater using battery and wire?

Yes, it is safe to use a water heater using battery and wire as long as it is installed and operated correctly. It is important to follow all safety precautions and guidelines provided by the manufacturer. Additionally, regular maintenance and inspections should be conducted to ensure the safety and efficiency of the heater.

5. Can a water heater using battery and wire be used in any type of water tank?

No, a water heater using battery and wire is designed to be used in specific types of water tanks, such as those made of metal or glass. It is not suitable for use in plastic or other non-metallic tanks as they may melt or become damaged when exposed to high heat. It is important to consult the manufacturer's instructions to ensure compatibility with your water tank.

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