1 / 4

Charge, potential difference, energy and current

Learn about charged objects, static electricity in industry, equations linking charge, current, potential difference and energy, and the importance of lightning conductors.

mware
Download Presentation

Charge, potential difference, energy and current

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Charge, potential difference, energy and current

  2. What does it mean if something is described as charged? the object has a net positive or negative charge due to electrons being taken away or given to the object (2 marks) • List 3 ways that static electricity is used in industry? Any three from: Electrostatic precipitator (smoke scrubbers in chimneys). Photocopiers. Printers. Powder coating/spraying. (3 marks) • For one of the above examples, describe how the process works. ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….(4 marks) • What is the equation that links charge, current and time? Q = It ...................................................(1mark) • What is the equation that links charge, potential difference and energy? E = QV................................(1 mark) • How much charge flows when a current of 2A flows for 30 seconds? ..............................60C........................(1mark) • What current flows if a charge of 300C flows for 3minutes? ……………………1.7A....................................(1 mark) • What current flows if a charge of 270C flows for 106seconds? …………………2.5A…………………………………….(1 mark) • A p.d. of 12V is applied across a resistor. 250C of charge passes. How much energy was dissipated by the resistor ? …...............................3000J.........................................(1 mark) • A current of 0.12A flows through a resistor which has a resistance of 150 Ohms, 300C of charge passes. How much energy was dissipated by the resistor? V = IR V = 18..18x300 = 5400J.............................(2 marks) • A light bulb releases 230J of energy when connected to a 11V battery. How much charge flowed in the circuit? …………………20.9C………………………………….……(1 mark)

  3. The diagram shows a charged thundercloud. (a) Why does the tree below the thundercloud become positively charged? electrons / negative charges are Repelled (1 mark) (b) The base of the cloud has a negative charge of 18 coulombs. The potential difference between the base of the cloud and the ground is 1 200 000 kilovolts. (i) Write down the equation that links charge, energy transferred and potential difference. energy (transferred) = potential difference × charge (accept E = V × Q, accept W = V × Q) (1 mark)

  4. (ii) Calculate the maximum energy that could be transferred to the ground by a lightning strike. Show clearly how you work out your answer. ......E = VQ = 1200000 x 18 = 21600000000.......... Maximum energy transferred =21 600 000 000 or 2.16 × 1010 joules (2 marks) (c) A lightning conductor is usually attached to tall buildings. This reduces the risk of damage by a lightning strike. Explain why the lightning conductor is made of copper. copper is a good (electrical) conductor or copper has a low Resistance (1 mark) ......................................................................................................... provides path for electrons / electricity / lightning to earth / ground / metal plate (1 mark)

More Related