Turn on thread page Beta
    • Thread Starter
    Offline

    1
    ReputationRep:
    I recently did an experiment on how the length of a nichrome wire affects the resistance. We got set some questions and I have no clue where to start
    a) Use the relationship R= ρL/ A + Ro, A= πr^2 and r=d/2 to show that
    R = (4ρ/ πd^2) L + Ro (where ρ= resistivity; Ro= resistance of connecting leads)
    b) Hence show that ρ= Gπd^2/ 4 (where G= gradient), my gradient was 5 which seems too big but I think my multimeter was on a different sensitivity setting so I think it is ok. Also should the graph be a straight line from the origin because as the relationship is directly proportional that's what I thought but I don't know what it is about practicals, I always doubt myself- I hate them so much
    Thanks in advance
    • Study Helper
    Offline

    19
    Study Helper
    (Original post by michelecorrrea)
    I recently did an experiment on how the length of a nichrome wire affects the resistance. We got set some questions and I have no clue where to start
    a) Use the relationship R= ρL/ A + Ro, A= πr^2 and r=d/2 to show that
    R = (4ρ/ πd^2) L + Ro (where ρ= resistivity; Ro= resistance of connecting leads)
    You can substitute in A= πr^2 into the equation R = (ρL/ A )+ Ro and play around with that a bit to get the desired result.

    b) Hence show that ρ= Gπd^2/ 4 (where G= gradient), my gradient was 5 which seems too big but I think my multimeter was on a different sensitivity setting so I think it is ok. Also should the graph be a straight line from the origin because as the relationship is directly proportional that's what I thought but I don't know what it is about practicals, I always doubt myself- I hate them so much
    Thanks in advance
    I guess that you plotted the resistance (on the y-axis) against the length? If so, compare:

    R = (4ρ/ πd^2) L + Ro to y = mx + c and see if you can get it from there.
    • Thread Starter
    Offline

    1
    ReputationRep:
    (Original post by usycool1)
    You can substitute in A= πr^2 into the equation R = (ρL/ A )+ Ro and play around with that a bit to get the desired result.



    I guess that you plotted the resistance (on the y-axis) against the length? If so, compare:

    R = (4ρ/ πd^2) L + Ro to y = mx + c and see if you can get it from there.
    Yeah resistance is on the y axis
    Thank you so much ... I love you more than words can express
 
 
 

University open days

  • University of Bradford
    All faculties Undergraduate
    Wed, 21 Nov '18
  • Buckinghamshire New University
    All Faculties Postgraduate
    Wed, 21 Nov '18
  • Heriot-Watt University
    All Schools Postgraduate
    Wed, 21 Nov '18
Poll
Black Friday: Yay or Nay?
Help with your A-levels

All the essentials

The adventure begins mug

Student life: what to expect

What it's really like going to uni

Rosette

Essay expert

Learn to write like a pro with our ultimate essay guide.

Uni match

Uni match

Our tool will help you find the perfect course for you

Study planner

Create a study plan

Get your head around what you need to do and when with the study planner tool.

Study planner

Resources by subject

Everything from mind maps to class notes.

Hands typing

Degrees without fees

Discover more about degree-level apprenticeships.

A student doing homework

Study tips from A* students

Students who got top grades in their A-levels share their secrets

Study help links and info

Can you help? Study help unanswered threadsRules and posting guidelines

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.