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Question 18M.2.SL.TZ1.4

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Date May 2018 Marks available [Maximum mark: 5] Reference code 18M.2.SL.TZ1.4
Level SL Paper 2 Time zone TZ1
Command term Calculate Question number 4 Adapted from N/A
4.
[Maximum mark: 5]
18M.2.SL.TZ1.4

An ohmic conductor is connected to an ideal ammeter and to a power supply of output voltage V.

M18/4/PHYSI/SP2/ENG/TZ1/04

The following data are available for the conductor:

                    density of free electrons     = 8.5 × 1022 cm−3

                    resistivity                          ρ = 1.7 × 10−8 Ωm

                    dimensions           w × h × l = 0.020 cm × 0.020 cm × 10 cm.

 

The ammeter reading is 2.0 A.

(a)

Calculate the resistance of the conductor.

[2]

Markscheme

1.7 × 10–8 ×  0.10 ( 0.02 × 10 − 2 ) 2

0.043 «Ω»

[2 marks]

(b)

Calculate the drift speed v of the electrons in the conductor in cm s–1. State your answer to an appropriate number of significant figures.

[3]

Markscheme

v «= I n e A » =  2 8.5 × 10 22 × 1.60 × 10 − 19 × 0.02 2

0.368 «cms–1»

0.37 «cms–1»

 

Award [2 max] if answer is not expressed to 2 sf.

[3 marks]

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