DP Physics (first assessment 2025)

Question 19M.2.SL.TZ2.9b

Date	May 2019	Marks available	[Maximum mark: 2]	Reference code	19M.2.SL.TZ2.9b
Level	SL	Paper	2	Time zone	TZ2
Command term	Determine	Question number	b	Adapted from	N/A

[Maximum mark: 2]

19M.2.SL.TZ2.9b

(b)

The diagram shows some of the electric field lines for two fixed, charged particles X and Y.

The magnitude of the charge on X is $Q$ and that on Y is $q$ . The distance between X and Y is 0.600 m. The distance between P and Y is 0.820 m.

At P the electric field is zero. Determine, to one significant figure, the ratio $\frac{Q}{q}$ .

[2]

Markscheme

$\frac{{kQ}}{{{{(0.600 + 0.820)}^2}}} = \frac{{kq}}{{{{0.820}^2}}}$ ✔

$\frac{Q}{q} = « \frac{{{{(0.600 + 0.820)}^2}}}{{{{0.820}^2}}} = 2.9988 \approx » 3$ ✔

Examiners report

The majority of candidates had an idea of the basic technique here but it was surprisingly common to see the squared missing from the expression for field strengths.

Syllabus sections

D. Fields » D.2 Electric and magnetic fields

Question 19M.2.SL.TZ2.9b

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