P3 0.0 / 5 ? PhysicsGCSEAQA Created by: LizzieCreated on: 11-05-13 18:35 What is the wavelength of an x ray? about the size of an atom 1 of 22 What is the frequency of ultrasound? 20,000Hz, higher than the upper limit of human hearing 2 of 22 How are ultrasound waves used for diagnosis? Partly reflected at a boundary between two different types of body tissue 3 of 22 Which way will a light ray refract when it goes from air to glass towards the normal 4 of 22 what is total internal reflection? when the angle of incidence is greater than than the critical anlge 5 of 22 What are optical fibres? thin, flexible pieces of glass used in endoscopes, by use total internal reflection 6 of 22 what controls how much light enters the eyes? the iris 7 of 22 where does light enter the eye? the pupil 8 of 22 what changes the thickness of the lens? the ciliary muscles attached to the suspensory ligaments 9 of 22 what helps the eye lens to focus light onto the retina? the cornea (the transparent layer) 10 of 22 what is the range of vision of the human eye? 25cm to infinity 11 of 22 How do treat someone who cannot see near objects because of a short eyeball/weak lens (long sightedness)? use a converging lens so light rays are focused on the retina 12 of 22 How do treat someone who cannot see distant objects because of a long eyeball (short sightedness)? use a diverging lens so light rays are focussed on the retina (instead of before it) 13 of 22 What is a moment? the turning effect of a force 14 of 22 What is the centripetal force? The resultant force that cause an object moving in a circle to accelerate 15 of 22 What does the time period of an oscillation (time taken to complete one cycle) depend on? the length of the pendulum 16 of 22 why will a pendulum with an oscillating motion come to rest if not pushed? because energy is transferred to friction at the top of the pendulum and due to air resistance 17 of 22 What is the motor effect? when a wire carrying a current is placed in a magnetic field, so it experiences a force 18 of 22 How is a pd induced across the ends of conductor? If an electrical conductor cuts through a magnetic field 19 of 22 what kind of transformer makes the pd across the secondary coil greater than that on the primary coil? a step up transformer 20 of 22 what kind of transformer makes the pd across the primary coil greater than that on the secondary coil? a step down transformer 21 of 22 Which transformer is much lighter and small and operates at a much higher frequency? a switch mode transformer 22 of 22
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