We use the inside of a pencil (graphite) to apply different "lengths of pencil" to the circuit. What relationship do you observe between length of graphite and deflection angle? Created by Brit Cruise.
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- That's pretty cool. What other materials could you use to get the same effect?(8 votes)
- in general, most of the conductors possess a linear variation of resistance with length at particular physical conditions..however the proportionality constant varies with any changes made in the physical conditions like temperature, material, etc.(5 votes)
- Okay, so now I know that resistance is proportional to Resistivity*length/area. I was recently reading a Science Olympiad question paper. There was a question that baffled me: If the length of the copper wire is doubled, what will be the effect on its resistance. I should think the answer is 2R. But apparently the answer is 4R. Why?(5 votes)
- This is an interesting question, but it's a trick. This question assumes you stretch the wire, rather than simply double the amount of wire. This decreases the cross sectional area as well. (will need to do these experiments next)(6 votes)
- Why does he use the water cup ? what is the use of it ?(2 votes)
- If you watch previous videos, you'll see why. As a short explanation, he uses the cup of water because it's the water and the zinc of the battery that cause a reaction, which is what is being measured.(1 vote)
- From what I observe, the metal clips are the best conductors and provide the highest deflection. As the length of the graphite increases, the deflection decreases. Does this prove a linear relationship between length of conductor and current. Maybe more of the conductor opposes the flow of current?(2 votes)
- yes ! resistance is equal to resistivity ( characteristic property of a material ) times length divided by cross sectional area . here area and resistivity being constant..as we alter the length..due to the linear variation of resistance..we end up getting lesser deflection !(3 votes)
- is this pencilly apparatus also called a potentiometer? and if so are potentiometers just resistors with a variable output?#(1 vote)
- Is there any other ways you can use graphite for besides using it for the inside of a pencil?(1 vote)
- I'm sure there are, most likely in factories somewhere. If you want details you could try looking it up on Google.(1 vote)
(pencil scratching) (water splashing in cup)