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1 markSound

CSEC Physics · May/June 2009 · Paper 2 · Question 3(b)(i)b)

Ultrasounds are used to determine a baby's growth. Sound pulses are directed at the baby's skull, and reflected pulses (echoes) from the front and back of the skull are detected and displayed on an oscilloscope, as shown in Figure 2.

In terms of the distances a and d, write an expression for the distance travelled by the sound pulse after reflection from the back of the skull to the sound detector.

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Other parts of this question

  1. 3(a)(i)Why does Ray A travel in a straight line from the object to the observer?[1 mark]
  2. 3(a)(ii)What is the name given to the bending of Ray B as it approaches the hot surface?[1 mark]
  3. 3(a)(iii)With reference to the normal, the temperature and the density of the air, explain the direction of the bending of Ray B at Point x.[2 marks]
  4. 3(a)(iv)The mirage is a virtual image. With reference to Rays B and C, explain how the mirage is formed and why it is described as a virtual image.[2 marks]
  5. 3(b)(i)a)In terms of the distances a and d, write an expression for the distance travelled by the sound pulse after reflection from the front of the skull to the sound…[1 mark]
  6. 3(b)(ii)a)Determine the difference in distance travelled between the first and the second echo[2 marks]
  7. 3(b)(ii)b)Determine the diameter, d, of the baby's skull.[1 mark]
  8. 3(c)(i)The object O is 100 m from the centre of the eye lens and the magnification of the eye lens is 0.005. Determine the distance of the retina from the centre of…[3 marks]
  9. 3(c)(ii)Write a formula for calculating the magnification of the eye lens using the object height and the image height[1 mark]

More practice: the rest of this paper · more Sound questions · all CSEC Physics past papers