Question 3 Explain why the choice of ultrasound frequency used in medical imaging is a compromise between image resolution and the effects of attenuateon. [1.3] Question 4 Compare medical ultrasound scanning with other forms of imaging (X-ray imaging and MRI for example), including resolution and safety issues. [1.4) Sumscut Question 5 a) Explain the conditions necessary for total internal reflection of light at the interface between two media. b) Describe and explain the structure of a step index optical fibre. c) Complete the following diagram to show how a ray of light can be transmitted from one end to another of a curved section of a fibre optic strand by repeated internal reflection. Core Cladding Light ray [2.1] Question 6 With the aid of a diagram, describe the structure of a flexible endoscope capable of carrying out minor surgical procedures