Had a go Nearly there Nailed it! Core. Key concepts. 2 Explain the difference between a base unit and a derived unit

Transcription

1 Out and about Core Key concepts 1 Complete the table for units of physical quantities and their abbreviations. ampere... joule... pascal Pa coulomb... mole... watt... newton... ohm... 2 Explain the difference between a base unit and a derived unit. (2 marks) (2 marks) 3 Convert each quantity. (a) 750 grams to kilograms 1000 g = 1 kg; 1000 W = 1 kw; 60 s = 1 minute; 1000 mm = 1 m; J = 1 MJ...kg (1 mark) (b) 0.75 kilowatts to watts (c) 25 minutes to seconds... W (1 mark)... s (1 mark) (d) 30 millimetres to metres...m (1 mark) (e) 3 megajoules to joules... J (1 mark) 4 Write each quantity in the unit shown and then in standard form. (a) frequency of 2.5 khz Hz: 2.5 khz = 2500 Hz standard form: Hz (2 marks) (b) length of 8 nm m:... standard form:... (2 marks) 5 Calculate the speed of a car that takes 10.5 s to travel 75 m. Give your answer to 5 significant figures. Look at the number that follows the significant figure you are asked to consider (in this case the 5th one). If it is greater than 5, round the 5th figure up, if it is less then round down, e.g would become to 5 significant figures. speed =... m/s (2 marks) 1

2 Colour of an object 1 (a) Give three examples of the reflection of waves. Consider all types of waves, not just light (3 marks) (b) Give an example of where specular reflection occurs. (1 mark) 2 Match the colour of light with the correct description. Colour red blue yellow violet Description shortest wavelength of visible light absorbed by a red object seen through a blue filter longest wavelength of visible light (4 marks) 3 Explain why a green object appears green in white light. The green object appears green because... and all other colours... (2 marks) 4 Explain, with the aid of a diagram, how diffuse reflection still obeys the law of reflection. You will need to draw a diagram of the microscopic, uneven surface of a material that shows how light is still reflected according to θi=θr but from several different angles of the surface. 34 (5 marks)

3 Investigating refraction 1 (a) Suggest a method that could be used to investigate the refraction of light using a glass block and a ray box. (4 marks) (b) Explain what conclusion you would expect to find using the method you have outlined in (a). Your answer should refer to the angle of incidence and the angle of refraction. When a light ray travels from air into a glass block... (2 marks) (c) (i) Explain what would be observed if the light ray, travelling through the air, entered the glass at an angle of 90 to the surface of the glass. (1 mark) (ii) Explain what would be happening that could not be observed in this experiment. (2 marks) 2 State three hazards associated with investigating reflection with a ray box and suggest safety measures that could be taken to minimise the risk. (3 marks) 3 The refraction of light waves through transparent materials can be modelled using a ripple tank. Describe what changes you would expect to observe in the waves when the depth of the water is made shallower by placing a glass sheet at an angle to the waves. Consider the waves being generated in deeper water and then moving into shallower water. 38 (2 marks)

4 Measuring radioactivity 1 In 1896 Henri Becquerel discovered that uranium salts led to a darkening of photographic film. Explain how this is used in the nuclear industry today. Photographic film is used by nuclear industry workers... This monitors levels of... (3 marks) 2 Complete the flow chart below to show how a Geiger Muller tube detects nuclear radiation. A thin wire à Atoms of argon are à Electrons travel à The amount of (4 marks) 3 A student claims that the more ionising the radiation, the more effective the G M tube is at detecting levels of radiation. Explain whether the student is correct. (3 marks) 4 Explain why photographic film badges have aluminium and lead sheets inserted in front of different parts of the photographic film. Aluminium will absorb some beta particles and lead will absorb some gamma waves. Absorption will depend on the thickness of the materials. (3 marks) 50

5 Wave equations 1 Whales communicate over long distances by sending sound waves through the oceans. It takes 20 seconds for the sound waves to travel in seawater between two whales 30 kilometres apart. Calculate the speed of sound in water in metres/second. Speed = Distance travelled by the waves (in metres) time taken... So... 2 A sound wave has a wavelength of m and a frequency of Hz. Calculate the speed of the wave. You may find this equation useful v = f λ or wave speed = frequency wavelength speed of sound =... m/s (3 marks) wave speed =... m/s (2 marks) 3 An icicle is melting into a pool of water. Drops fall every half a second, producing small waves that travel across the water at 0.05 m/s. Calculate the wavelength of the small waves. State the units. Remember to write down the equation you are using before you substitute values. wavelength =... unit... (3 marks) 4 A satellite sends signals to your TV using radio waves. It takes 0.12 s for the radio waves to travel from the satellite to your TV. The speed of light is m/s. Calculate the distance of the satellite above the Earth in kilometres. You may find this equation useful s = d t or speed = distance time distance =... km (3 marks) 24

6 Paper 2 Transformers 1 Two types of transformers are used in the National Grid. Name them and describe their use. (2 marks) 2 (a) Give the result of increasing voltage before it is transmitted in the National Grid. (1 mark) (b) Explain how this helps to conserve energy. (2 marks) 3 A laptop computer needs a voltage of 19 V. It is connected to the 230 V mains electricity supply using a transformer with 380 turns on the secondary coil. Calculate the number of turns on the primary coil of the transformer. V p /V s = n p /n s, V p =..., V s =..., n s =... n p = n s V p /V s = Rearrange the equation and substitute the known values. number of turns on primary coil =... (3 marks) 4 A transformer has 600 turns on its primary coil and 20 turns on its secondary coil. The primary voltage is 360 V. (a) Explain what type of transformer it is. (2 marks) (b) Calculate the secondary voltage. secondary voltage =...V (3 marks) 104

7