DP Physics (last assessment 2024)

Question 18M.3.SL.TZ1.b.ii

Date	May 2018	Marks available	[Maximum mark: 3]	Reference code	18M.3.SL.TZ1.b.ii
Level	SL	Paper	3	Time zone	TZ1
Command term	Determine	Question number	b.ii	Adapted from	N/A

b.ii.

[Maximum mark: 3]

18M.3.SL.TZ1.b.ii

A magnetized needle is oscillating on a string about a vertical axis in a horizontal magneticfield B. The time for 10 oscillations is recorded for different values of B.

M18/4/PHYSI/SP3/ENG/TZ1/01_01

The graph shows the variation with B of the time for 10 oscillations together with the uncertainties in the time measurements. The uncertainty in B is negligible.

A student forms a hypothesis that the period of one oscillation P is given by:

$P = \frac{K}{{\sqrt B }}$

where K is a constant.

Determine the value of K using the point for which B = 0.005 T.

State the uncertainty in K to an appropriate number of significant figures.

[3]

Markscheme

$K = \sqrt {0.005} \times 0.84 = 0.059$

« $\frac{{\Delta K}}{K} = \frac{{\Delta P}}{P}$ »