DP Physics (last assessment 2024)

Question 17N.3.HL.TZ0.16

Date	November 2017	Marks available	[Maximum mark: 4]	Reference code	17N.3.HL.TZ0.16
Level	HL	Paper	3	Time zone	TZ0
Command term	Estimate, Show that	Question number	16	Adapted from	N/A

16.

[Maximum mark: 4]

17N.3.HL.TZ0.16

An X-ray beam of intensity I₀ is incident on lead. After travelling a distance x through the lead the intensity of the beam is reduced to I.

The graph shows the variation of ln $\left( {\frac{I}{{{I_0}}}} \right)$ with x.

(a)

Show that the attenuation coefficient of lead is 60 cm^–1.

[2]

Markscheme

evidence of finding the gradient

μ = «– gradient =» 59.9 «cm^–1»

(b)

A technician operates an X-ray machine that takes 100 images each day. Estimate the width of the lead screen that is required so that the total exposure of the technician in 250 working days is equal to the exposure that the technician would receive from one X-ray exposure without the lead screen.

[2]

Markscheme

I = $\frac{{{I_0}}}{{25000}}$

«ln 25000 = μx» x = 0.17 «cm» or 1.7 «mm»

Syllabus sections

Option C: Imaging

Option C: Imaging » Option C: Imaging (Additional higher level option topics) » C.4 – Medical imaging (HL only)

Option C: Imaging » Option C: Imaging (Additional higher level option topics)

Question 17N.3.HL.TZ0.16

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