Science Home learning Jamie.venning@astreadearne.org, Thomas.bagnall@astreadearne.org, Danie.cadman@astreadearne.org, sean.guy@astreadearne.org, Kayleigh.smith@astreadearne.org, Robert.gray@astreadearne.org, Vicky.conway@astreadearne.org, dawn.brough@astreadearne.org, Hannah.szabo@astreadearne.org, Richard.white@astreadearne.org, victor.oczadly@astreadearne.org, Twitter Link: @Dearnescience L6 Power Year: 10 Topic: Physics Unit: Energy Date Set: Information to read / watch: https://classroom.thenational.academy/subjects-by-key-stage/key-stage-4 Click on Physics, then Energy Complete lesson 6 Power https://app.senecalearning.com/dashboard Go to AQA Physics higher or foundation and choose topic Energy Complete section 1.1.3 Objectives: Define power and state the equation Complete power calculations Give examples that illustrate the definition of power Additional Websites: GCSE Combined Science - AQA Trilogy - BBC Bitesize Click Energy and review the topic Page 1 of 8 ME Task Lesson 6: Power Define power and give the equation. __________________________________________________________________________________ __________________________________________________________________________________ 1. Convert the following units (10) Quantity 1 2 3 4 5 6 7 8 9 10 Convert into…. 900W 1.2kW 430kJ 990kJ 9J 0.03kW 20kJ 12.3Mw 300J 0.001MW kW W J MJ kJ W MJ kW MJ kW E P x t Include the units in ALL of the following answers 2. How much energy does a pair of 800W hair straighteners transfer every second? (1) 3. 1.5kJ of energy are used every second by a microwave oven, what is the power rating of the oven? (3) 4. 0.8MJ of energy are used by a blender in 3 and a half minutes. What is the power rating on the blender? (3) 5. A 3kW oven supplied with 9kJ of energy. How many seconds can it be run for? (3) Page 2 of 8 6. A 2.1W iPod is used for 30 minutes. How much energy does it use? (3) 7. Batman recharges his Bat-taser with 2.5MJ of energy in 15 minutes. How much Power does it draw from the mains? (3) 8. Spiderman’s nemesis Electro delivers 4kJ of electrical energy in half a second. How powerful is he? (3) 9. A 3kW oven supplied with 9MJ of energy. How many minutes can it be run for? (4) 10. The Tesla Roadster electric car is rated at 16.8kW. How much energy does it use during a one hour drive? Answer in MJ (3) Page 3 of 8 Power- Challenge Task 1. (a) The table shows the power rating and operating current for several household appliances. Appliance Power (watt) Current (ampere) cooker 6000 25.0 iron 960 4.0 food mixer 480 2.0 television 180 0.75 table lamp 60 0.25 (i) Which appliance costs most to run for an hour? Give a reason for your answer. Appliance ......................................................................................................... Reason .............................................................................................................. (2) (ii) Each of the appliances listed uses 240 volts. Explain why the cooker has the smallest resistance of these appliances. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (2) (iii) A cooker is always on a separate circuit with a thick cable. Tick the two boxes to show the reasons for this. Thick cables have a lower resistance. Thick cables are easy to insulate. Page 4 of 8 Thick cables melt at a higher temperature. Thick cables produce less heat. (2) (b) Electrical lighting in a house uses parallel circuits instead of series circuits. State two reasons why parallel circuits are used for domestic lighting circuits. 1 ................................................................................................................................. .................................................................................................................................... 2 ................................................................................................................................. .................................................................................................................................... (2) (Total 8 marks) Page 5 of 8 Mark Scheme: 1. Con