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Description
Flashcards by Gabriella Brown, updated more than 1 year ago
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Created by Gabriella Brown
almost 2 years ago
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| Question | Answer |
| What is an electric field? | A region around a charged object where other charged objects would experience a force. |
| Opposite charges (a)_______ Similar or like charges (b)_____ | (a) attract (b) repel |
| What is the difference between a charge with -1 vs -3? | The force around the -3 charge is stronger due to more field lines around it. |
| Why does field strength decrease as you get further away? | As you get further away, field lines get further apart and the field density decreases. |
| What is static electricity and how is it caused? | Static electricity is the electrical charge that occurs when insulators gain electrons. This is usually due to an insulator and another material rubbing together and the insulator gaining electrons so that it has a negative charge. |
| Why, when using a Van de Graaff generator, do you get sparks? | Charge builds up to produce a v. strong electric field. This causes the air to become ionised. Charge flows through the air from -ve to +ve. |
| (a) What is current and (b) what are the units? | The rate of flow of charge. 1 amp of current is Coulomb of charge flowing through something per second. |
| What is the equation for current? | I (Current, A) = Q (Charge flow, C)/t (time, s) |
| Give the definition of "potential difference". | The energy change (work done) per coulomb of charge to move from one point to another. |
| What is the equation for potential difference? | V (p.d., V) = E or W (energy change, J)/Q (charge flow, C) |
| what does it mean if the p.d. is 5V? | 5J of work is done to get through the resistor. |
| What is resistance? | Resistance is the p.d. needed to produce 1 amp of current. |
| Resistance is (a)________ proportional to p.d./Voltage. Resistance is (b)_________ proportional to current. | (a) directly (b) inversely |
| What is resistance measured in? | Ohms (omega symbol) |
| What is the equation for resistance? | R (resistance, ohms) = V (p.d., V)/I (current, A) |
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