How Do You Calculate Resistance and Current in a Carbon Block Using Ohm's Law?

AI Thread Summary
To calculate the resistance of a carbon block, the formula R = pL/A is used, where p is resistivity, L is the length, and A is the cross-sectional area. The block measures 3cm in length with a square cross-section of 0.5cm by 0.5cm, leading to an area of 0.25cm². With a potential difference of 8.4V applied, users seek to determine both the resistance and the current through the block. Clarification on the block's shape, described as a cuboid, aids understanding of the problem. This discussion emphasizes the importance of visualizing the geometry for accurate calculations.
LeakyFrog
Messages
21
Reaction score
0

Homework Statement


A block of carbon is 3cm long and has a square cross section whose sides are .5cm long. A potential difference of 8.4V maintained across its length.
a)What is the resistance of the block?
b)What is the current in this resistor?


Homework Equations


R=pL/A
where p is resistivity


The Attempt at a Solution


I'm fairly certain i can solve this problem right quick if I could understand what exactly the block looked like. The description just doesn't make sense to me. I'm not sure if you can draw pictures on this or not but a picture would be helpful if someone can make one. Thanks.
 
Physics news on Phys.org
From what I've read the block is a cuboid. Imagine a square that's 0.5cm by 0.5cm, now stretch that back in the third dimension by 3cm, and Bob's your uncle. A similar shape to a packet of gum.

Juicy+fruit.gif
 
thanks dude (or dudette)! helped a bunch!
 
No worries mate.
 
Thread 'Voltmeter readings for this circuit with switches'

Thread 'Voltmeter readings for this circuit with switches'

TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
View full post »
Thread 'Struggling to make relation between elastic force and height'

Thread 'Struggling to make relation between elastic force and height'

Hello guys this is what I tried so far. I used the UTS to calculate the force it needs when the rope tears. My idea was to make a relationship/ function that would give me the force depending on height. Yeah i couldnt find a way to solve it. I also thought about how I could use hooks law (how it was given to me in my script) with the thought of instead of having two part of a rope id have one singular rope from the middle to the top where I could find the difference in height. But the...
View full post »

Similar threads

Ohm's Law confusion -- How to handle an incandescent bulb?
Replies
7
Views
2K
Ohm's law and Kirchoff — What am I missing?
Replies
4
Views
2K
Ohm's Law Validity: Does it Change with Heat?
Replies
1
Views
2K
Understanding Power Equations: How Do You Solve for V2 and R in Ohm's Law?
Replies
4
Views
3K
I Resistance and specific resistance relationships
Replies
16
Views
2K
How to calculate resistance in a combined circuit using V&I
Replies
4
Views
2K
How can I represent these resistances on a diagram?
Replies
21
Views
2K
Calculating Resistance in a Circuit using Kirchhoff's Laws
Replies
9
Views
2K
Calculating current with and without internal resistance
Replies
6
Views
3K
Learning Ohm's Law: Broad vs. In-Depth?
Replies
5
Views
2K

Hot Threads

Recent Insights

Back
Top