Holy Cross High School Electrical Circuits And Energy Generation Homework

Transcription

1 Holy Cross High School Electrical Circuits And Energy Generation Homework DO NOT WRITE ON THIS BOOKLET Answer all questions in your jotter. Please return this booklet to your science teacher at the end of the Electricity and Energy topic.

2 Homework Sheet 1 Circuit Symbols Copy the descriptions below and fill in the gaps. Next to the statement draw the symbol for the device a) BATTERY Supplies energy. b) LAMP Converts electrical energy to energy. c) SWITCH An open switch breaks a circuit. A closed switch a circuit. d) Motor This converts electrical energy into energy. e) RESISTOR Converts electrical energy into.

3 Homework Sheet 2 Series & Parallel Circuits Diagram 1 Diagram 2 B A C 1. What components do the letters A, B and C represent? A... B... C What is the name given to the way the bulbs are arranged in Diagram 1? 3. What is the name given to the way the bulbs are arranged in Diagram 2? 4. In a series circuit, how is the brightness of the first bulb affected when the second bulb is connected? 5. In a series circuit, what would happen if one of the bulbs was broken? Explain why this happens? 6. In a Parallel circuit, what would happen if one of the bulbs was broken? Explain why this happens?

4 Homework Sheet 3 Current and Voltage 1. Using words from the wordbank below copy and complete the following paragraphs. Words may be used on more than occasion. series ammeter parallel A volts amps voltmeter V a) Current is measured using an. Current is measured in using the symbol. To measure current through a component, the is always connected in with the component. This means breaking the circuit to connect the. b) Voltage is measured using a. Voltage is measured in usually given the symbol. To measure voltage across a component, the is always connected in with the component. This can be done without breaking the circuit. The forms a parallel branch across the component.

5 2. Write down the correct option in each of the following examples. a) When components are connected in series there is only one two more than one path for the current to take to pass through them. b) When components are connected in parallel there is only one two more than one path for the current to take to pass through them. 3. Redraw the following circuit showing an ammeter in the correct position. 4. Redraw the following circuit showing a voltmeter in the correct position.

6 Homework Sheet 4 Current and Voltage calculations 1. In the following circuit find the current reading on Ammeter A 2 and the current through each lamp. A 2 A 1 0.2A Lamp1 Lamp 2 Current through A 2 is. Current through lamp 1 is. Current through lamp 2 is. 2. Vs V 1 V 2 V1 = 6V V2 = 6V Find the supply voltage in the circuit above. Supply voltage =

7 3. Calculate the reading on ammeter A3. A 3 A 1 A 2 A 1 = 0.5A A 2 = 0.5A Current through A 3 =. 4. In the circuit below V1 and V2 both read 6V. What is the voltage across the supply? Vs V 1 V 2 Voltage across the supply =

8 5. Dan and Tom build a circuit like the one shown below. X (a) Name the component labelled X... (b) What are Dan and Tom using the component labelled X to measure?... (c) Dan says, Ammeter 1 will show a lower reading than Ammeter 2 because the bulbs in the circuit use up the current. Tom says, Ammeter 1 will show the same reading as Ammeter 2 because current is not used up. Who is right?... (d) If Ammeter 1 has a reading of 1.5A, what reading will Ammeter 2 show?...a

9 Homework Sheet 5 Before 1991 all radios needed to be connected to the mains or use cells (batteries) to work. However, there are many parts of the world where there is no mains electricity and it is difficult to buy batteries. Trevor Bayliss was born in London in He studied engineering at a local college after leaving school and then spent two years in the army. After leaving the army he became a salesman and quickly progressed to working in research and development. He was very interested in inventing things. In 1991, Trevor watched a television programme about the spread of AIDS in Africa. He realised that many people in Africa were too poor to buy cells for radios and so they could not listen to radio programmes that told them how they could avoid getting AIDS. Trevor set out to develop a wind-up radio so they could listen without needing to buy cells. His first working example (or prototype) ran for 14 minutes. As the radio is wound up by hand, energy is stored inside the radio by winding up a spring just like in clockwork toys. When the radio is used the stored energy is transferred to make the radio work. Trevor needed money to set up a factory to make the radios, but he could not get anyone interested until 1994, when the radio was featured on a TV programme. The idea quickly caught on and a large company provided the money needed. Engineers from Bristol University helped to develop Trevor s invention so that it could be built in a new factory in South Africa. Charities bought radios to give to people in Africa. In 1996, the radio featured in a documentary on television and it was awarded the BBC Design Award for Best Product and Best Design. The Freeplay radio was offered for sale in the UK in Later models have a solar cell to extend the play time. Since then the company has developed other products powered by humans or by sunlight. Its products include torches and mobile phone chargers. 1 Why did Trevor Bayliss decide to invent a wind-up radio? 2 What is a prototype? 3 Why did Trevor need the help of engineers from Bristol University? 4 Why did he need money before he could start selling his radios? 5 Why is a wind-up radio useful in remote areas of the world? 6 What are the disadvantages of using a wind-up radio? 7 Would the solar cells always extend the playing time? Explain your answer. 8 Why might a person in this country want to use a Freeplay torch or mobile phone charger?

10 Homework Sheet 6 Generating Electricity and Fossil Fuels 1. What are the main parts of an electrical generator and how can we use these to generate electricity 2. How can you increase the volume of electricity being generated? 3. What are the similarities between coal and oil and gas? 4. What are the differences between coal and oil and gas? 5. What is a fossil fuel? 6. Thinking about the way fossil fuels are made, what is one of the problems with relying on them as an energy source? 7. Complete the table below to show the energy change in each part of the power station Part of Power Station Furnace Boiler Turbine Generator Energy Change 8. Give one advantage and one disadvantage to nuclear energy

11 Homework Sheet 7 Crossword Copy and complete the crossword in your jotter Across: 3. Coal, oil and gas are known as the fuels. 4. Resources that will not run out. 3 Down: 1. The type of energy stored in food. 2. The unit of energy It will burn to release energy. 4 True or False Answer the following questions with a true or false in your jotter 1. Oil is formed from Dead Sea creatures Energy is lost when electricity passes through a bulb The circuit component which provides the energy is called the cell 4. Solar power is more reliable than hydroelectric power Nuclear energy resources are non-renewable... Word Match Copy and join the word to the correct definition. Hydroelectricity... Solar power... Geothermal... Biomass......uses heat from the Earth to generate electricity....generating using the energy of falling water...organic material burned to release energy...uses energy from the Sun to generate electricity. Wordfill copy and complete the following paragraph F fuels take m of years to form. We are using these resources at a much f rate they are n -r. Eventually these resources will run out so we need to use alternative energy resources to generate e which are r, such as the Sun, wind and moving water.