DP Physics (first assessment 2025)

Question 22N.1A.SL.TZ0.16

Date	November 2022	Marks available	[Maximum mark: 1]	Reference code	22N.1A.SL.TZ0.16
Level	SL	Paper	1A	Time zone	TZ0
Command term		Question number	16	Adapted from	N/A

16.

[Maximum mark: 1]

22N.1A.SL.TZ0.16

Two copper wires of equal lengths but different diameters are used to connect a cell to a load. Wire 1 has a diameter M, wire 2 has a diameter 2M. The electron drift velocities in wires 1 and 2 are $v_{1}$ and $v_{2}$ .

What is $\frac{v_{2}}{v_{1}}$ ?

A. $4$

B. $2$

C. $\frac{1}{2}$

D. $\frac{1}{4}$

[1]

Markscheme

Examiners report

A moderately difficult question, with incorrect alternative A selected by a significant fraction of the candidates. Alternative A represents the reciprocal of the correct answer, suggesting an algebraic problem with manipulating fractions. The question implies equal current in both wires and equal carrier density. From drift speed equation, a 4× greater cross-sectional area of wire 2 results in a 4× smaller drift speed of charge carriers.

Syllabus sections

B. The particulate nature of matter

B. The particulate nature of matter » B.5 Current and circuits

Question 22N.1A.SL.TZ0.16

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