Resistance and Electrical Work These flashcards cover resistance, Ohm's Law and electrical work within the electricity topic. 0.0 / 5 ? PhysicsElectricityGCSEAQA Created by: 123Created on: 16-11-20 17:56 What is Ohm's Law? Potential difference = current x resistance 1 of 22 What is resistance? A measure for how difficult it is for current to flow through a component. 2 of 22 What 2 things affect the size of a current? 1. The resistance: If the resistance increases, the current decreases. 2. The potential difference: If the potential difference increases, the current will also increase. 3 of 22 What is resistance measured in? Ohms (Ω) 4 of 22 What's the equation for resistance? Resistance = Potential Difference ÷ Current R = V ÷ I 5 of 22 How do we measure the resistance in a circuit? Measure the potential difference across the component by using a voltmeter to find the resistance of the component. Use an ammeter to measure the current flowing through a component. 6 of 22 How does the length of the wire affect the resistance? The longer the wire the higher the resistance. 7 of 22 What does the line on a current-voltage graph for a resistor look like? It's a straight line going through 0. 8 of 22 What does the current-voltage graph for a resistor tell us about resistance? It is constant. 9 of 22 What is the slope equal to on the resistance graph? 1 ÷ resistance 10 of 22 What does a current-voltage graph look like for a filament lamp? It curves into a straight-ish line then curves back out at the top. 11 of 22 Does the filament lamp obey Ohm's Law? No it doesn't. 12 of 22 What does a current-voltage graph for a diode look like? A straight line a long the x-axis on the left hand side and then curves up on the right hand side. 13 of 22 Does the diode obey Ohm's Law? No it doesn't. 14 of 22 What's and Ohmic conductor? A conductor that obeys Ohm's Law. 15 of 22 What is the relationship between the current through the ohmic conductor and potential difference across the resistor? The current is directly proportional to the potential difference. This means that the resistance remains constant as the current changes. 16 of 22 What makes the current flow in an electrical circuit? The energy source (battery or power supply). 17 of 22 What does the flow of current transfer? It transfers energy from the energy source to the components. 18 of 22 What do components transfer? They transfer their energy into the surroundings. 19 of 22 What is power? The rate of energy transfer to a component. 20 of 22 What is the equation for power? P = I x V P = I (squared) x R 21 of 22 What's the equation for total energy transferred? E = P x t 22 of 22
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