please stick the barcode label here. phy paper 2 ... · 012-dse phy paper 2 please stick the...

012-DSEPHYPAPER 2

Please stick the barcode label here.

HONG KONG EXAMINATIONS AND ASSESSMENT AUTHORITYHONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION 2012

PHYSICS PAPER 2

Question-Answer Book

11.45 am - 12.45 pm (1 hour) This paper must be answered in English

INSTRUCTIONS

[ Candidate Number

(1)

(2)

(3)

(4)

(5)

(6)

(7)

After the announcement of the start of theexamination, you should first write your Candidate Number in the space provided on and stickbarcode labels in the spaces provided on Pages 1,3, 5, 7 and 9.

This paper consists of FOUR sections, Sections A, 8, C and D. Each section contains eight multiplechoice questions and one structured question whichcarries 10 marks. Attempt ALL questions in anyTWO sections.

Write your answers in the spaces provided in thisQuestion-Answer Book. Do not write in the margins.Answers written in the margins will not be marked.For multiple-choice questions, blacken theappropriate circle with an HB pencil. You shouldmark only ONE answer for each question. If youmark more than one answer, you will receive NOMARKS for that question.

Graph paper and supplementary answer sheets willbe provided on request. Write your candidatenumber, mark the question number box and stick abarcode label on each sheet, and fasten them withstring INSIDE this Question-Answer Book.

The diagrams in this paper are NOT necessarilydrawn to scale.

The last two pages of this Question-Answer Bookcontain a list of data, formulae and relationshipswhich you may find useful.

No extra time will be given to candidates for stickingon the barcode labels or filling in the questionnumber boxes after the Time is up'announcement.

2012-DSE-PHY 2-1 39 II JI Jll 11111 IJ Ill 更多試卷歡迎瀏覽 http://dsepp.com

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Q.4: Structured question

(a) Figure 4.1 shows a cross-section of a piece of bone with 5.8 cm thickness situated below a layer of soft tissuethat is 2.0 cm thick. An ultrasound transducer with coupling gel is applied to the skin. The ultrasound pulsesreflected from various boundaries A, B and Care displayed on a CRO.

ultrasound transducer

Figure 4.1

coupling gel

2.0cm

skin

'B I,,,,, .. .,.,.,.,.,.,.,,, .

、soft5.8 cm ,,::::hrir:ii!i:> tissue

(i) Find the ratio of the speed of ultrasound in bone to that in soft tissue. (2 marks)

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The values of acoustic impedance of various body tissues to the ultrasound used are tabulated below.

淤，涑

soft tissue (average) bone

(ii) If the speed of ultrasound in soft tissue is 1580 m s舌estimate the density of bone. (3 marks)

Answers written in the margins will not be marked.

2012-DSE-PHY 2-17 55 更多試卷歡迎瀏覽 http://dsepp.com

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