Edexcel A-Level Physics AS Linear Relationships

Pearson Edexcel International Advanced Subsidiary/Advanced Level in Physics, Issue 3, July 2021Physics XPH11/YPH11

Review linear relationships in Edexcel A-Level Physics through y = mx + c comparisons, graph validity checks and constant-gradient arguments.

How this is tested

rearrange a physical equation into y = mx + c form to justify a straight-line graph

[Maximum number: 2]

The absorption of beta particles in aluminium can be investigated using the apparatus shown.

A student planned to test whether beta particles are absorbed by aluminium according to the relationship

C=C_{0} \mathrm{e}^{-\mu x}

where
C is the count rate when the thickness of the aluminium sheet is x
$C_{0}$ is the count rate with no aluminium sheet $\mu$ is a constant.

Explain why a graph of $\ln C$ against x could be used to test the validity of this relationship.