Sp3 conservation of energy First term Revision Paper - Physics Year 9 1. A student makes a solar water heater using a hosepipe. He paints the hosepipe black and fills it with water. He coils the hosepipe and fixes it into an open metal box as shown. The student puts a thermometer in each end of the hosepipe. The Sun shines on the hosepipe and heats the water. (a) Complete the sentence by putting a circle next to your answer. The hosepipe is painted black because blackened surfaces are A good emitters of radiation B poor emitters of radiation C good absorbers of radiation D poor absorbers of radiation (b) At first, the temperature of the water in the pipe increases. After a while, the temperature becomes constant. (i) Suggest two changes to the box which would increase the constant temperature reached. (2) (ii) Explain why the water reaches a constant temperature. (3) (c) Some of the solar energy incident on the solar water heater is reflected. The rest is absorbed. The diagram gives some information about energy transfer Calculate the efficiency of the heater. (2) 2. The diagram shows Simon s clock. Once a week, Simon turns a key to tighten the spring. The spring uncoils slowly to keep the clock working. (a) Which type of energy is stored in the tightened spring? A chemical energy C gravitational potential energy B elastic potential energy D thermal energy Page 1 of 8
(b) Every hour, the clock chimes to remind Simon of the time. The clock lifts a small hammer. The hammer falls and rings a little bell. The diagram shows what happens to the energy from the falling hammer. (i) Calculate the energy wasted. (ii) Calculate the efficiency of this process. (iii) Suggest what happens to the wasted energy. (2) *(c) The clock uses a pendulum. The pendulum is a metal rod with a large mass at the end. The mass swings from side to side.the spring keeps the pendulum swinging without stopping. Describe the energy changes that happen as the pendulum continues to swing from side to side. (6) 3. A student uses a solar powered battery charger to charge some batteries (a) The diagram is an energy transfer diagram for a battery being charged. Use words from the box to complete the energy transfer diagram. (2) Page 2 of 8
(b) The following arrangement is used as a solar powered shower. The bag is left out in the sunlight during the day. (i) Explain what colour the bag should be to heat the water to the highest temperature. (2) (ii) On a sunny day the bag is filled with cold water. Explain why the temperature of the water increases and then stays constant. (3) 4. *One way of producing electricity from a renewable source is tidal power. A dam is built across the mouth of a river. Tidal water gets trapped behind the dam. The trapped water is used to generate electricity. Discuss the advantages and disadvantages of using tidal power rather than other methods of generating electricity. (6) Page 3 of 8
SP 4 waves 1. a) ) The diagram shows the wave as it passes by the two floats. (i) (ii) The wavelength of the wave is 0.8 m. Calculate the distance between the floats. The frequency of the wave is 0.4 Hz. How many complete wavelengths pass each float in 20 s? (iii) A man on the shore observes the wave. Suggest one piece of information the man could gain about the boat by observing the wave that made it. (a) The wave reaches shallow water before it reaches the shore. Water waves travel more slowly in shallow water. The diagram shows the wave as it reaches the shallow water. Complete the diagram to show how the wave travels in the shallow water. (3) 2. (a) The diagram represents water waves travelling from deep water into an area of much shallower water. (i) (ii) State the name of the effect shown in this diagram Complete the sentence by putting a cross ( X) in the box next to your answer. When the waves go from deep water to shallow water, the (1) (iii) Explain another change which can be seen from the diagram when the waves go from deep water to shallow water Page 4 of 8
(b) The photograph shows a floating buoy used to warn boats about shallow water. The buoy has a lamp and a bell. Explain the difference between transverse and longitudinal waves by referring to sound from the bell and the light from the lamp. (3) 3. (a) Some students are investigating waves. They produce waves by moving a piece of wood up and down in a tank of water. The diagram shows the waves over a distance of 60 cm. (i) State the number of wavelengths shown on the diagram. (ii) Calculate the wavelength of the waves. (b) The student produce different wave. This wave has a frequency of 1.7 Hz and a wavelength of 8.0 cm. Calculate the speed of this wave. 4. A sound wave in air is made up of compressions and rarefactions. (i) State what is meant by a compression. (ii) State what is meant by a rarefaction. (b) The distance between two consecutive rarefactions in a sound wave is 2.5 m. The speed of sound in air is 330 m / s. Calculate the frequency of this sound wave. Electromagnetic spectrum (a) A student investigates the spectrum produced by visible light. The diagram shows some of the equipment she uses. She uses a piece of glass to split up the light into its colours. (i) Which of the following would be the best shape to use? Page 5 of 8
Put a cross ( ) in the box next to your answer. (ii) Each colour has a different wavelength. List the other colours in order of wavelength. Three have been done for you. SP5. Ray Diagram 1. An object is placed in front of a thin converging lens. The diagram shows the paths of two rays from the top of the object. An image of the object is formed on a screen to the right of the lens. How does this image compare with the object? A It is larger and inverted. B It is larger and the same way up. C It is smaller and inverted. D It is smaller and the same way up. 2. (a) Long sight can be corrected by wearing spectacles with converging (convex) lenses. A lens in these spectacles has a power of +3.2 dioptres. Calculate the focal length of this lens. (b) The diagram shows that his eye lens is not able to focus light on the retina. Complete the diagram below to show how the lens below is able to correct the man s vision. Page 6 of 8
3. (a) Complete the diagram below to show the path the light ray takes in air. (b) Janine examines an object through a convex image with focal length, F. Complete the path of light ray A through the lens below to show the position of the image. (c ) Complete the ray diagram below to show the position of the image. Page 7 of 8
4) a). The diagram below shows white light shining onto a green filter, followed by a red filter. Label the colour of light which passes through the green filter at point A. b). What colour light, if any, would be seen at point B? Explain your answer..c) What would happen if you shone blue light onto a red filter? Explain your answer. Page 8 of 8