FOLLOW US ON TWITTER
SHARE THIS PAGE ON FACEBOOK, TWITTER, WHATSAPP ... USING THE BUTTONS ON THE LEFT


YOUR PARTICIPATION FOR THE GROWTH OF PHYSICS REFERENCE BLOG

Saturday, November 9, 2019

The diagram shows a graph. For a uniform metallic wire, what could the graph not represent?


Question 17
The diagram shows a graph.

For a uniform metallic wire, what could the graph not represent?

y-axis                          x-axis
A          current                         potential difference
B          resistance                    length
C         resistance                    temperature in °C
D         potential difference     current





Reference: Past Exam Paper – November 2015 Paper 11 Q31





Solution:
Answer: C.

A uniform metallic wire obeys Ohm’s law (V = IR). So, a current-p.d. graph and a p.d.-current graph would be straight line. [A and D incorrect]


Resistance of wire: R = ρL / A
So, a resistance-length graph would also be a straight line. [B incorrect]


A graph of resistance against temperature will not be a straight line as the resistance of the metal wire increases with temperature. The higher the temperature, the greater the increase in temperature. So, the graph would be a curve, not a straight line.

No comments:

Post a Comment

If it's a past exam question, do not include links to the paper. Only the reference.
Comments will only be published after moderation

Currently Viewing: Physics Reference | The diagram shows a graph. For a uniform metallic wire, what could the graph not represent?