How much heat?
Current, material, thickness, length and time all matter.
One cell or two
You pass current through the same nichrome wire, first from 1 cell and then from 2 cells.
Which do you expect to make more heat in the wire?
What this lesson covers
The idea
The heat generated in a wire depends on the magnitude of the current, the material, thickness and length of the wire, and the duration for which the current flows.
One cell or two
You pass current through the same nichrome wire, first from 1 cell and then from 2 cells.
Which do you expect to make more heat in the wire?
- 2 cells
- 1 cell
- Exactly the same
Compare the set-ups
Try 1 cell and 2 cells. Slide the time to the right each time. Watch the warmth.
More than one reason
With 2 cells more heat was generated, because the heat depends on the size of the current. It also depends on the material, the thickness and the length of the wire, and on how long the current flows.
The heat generated in a wire depends on the magnitude of the current, the material, thickness and length of the wire, and the duration for which the current flows.
Notes
The heat generated in a wire depends on the current, the material, thickness and length of the wire, and the duration of the current.
Check yourself
Which of these does the heat generated in a wire depend on?
In the activity, 2 cells generated more heat than 1 cell. This is because heat depends on …
You want to check if the material of a wire changes the heat. Which two wires should you compare?
The heat depends on the current, the material, the thickness, the length and the duration. How many things is that?
Answer: 5
Current, material, thickness, length and duration are 5 things.
- The time for which the current flows — correct. Yes!
- The colour of the cell. The heat depends on the current, material, thickness, length and duration.
- The weather outside. The heat depends on the current, material, thickness, length and duration.
- the colour of the wire. The heat depends on the amount of current.
- the magnitude of the electric current — correct. Yes!
- the shape of the cell. The heat depends on the amount of current.
- Two copper wires of the same size and length. They are the same material, so you cannot compare materials.
- A thick copper wire and a thin copper wire. That changes the thickness, not the material.
- A copper wire and a nichrome wire of the same size and length — correct. Yes!