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4 Cards in this Set
- Front
- Back
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Why is there an increase in energy stored by the capacitor when the polythene sheet is pulled out from between the plates? |
Because the dielectric molecules align in the field with positive charged end towards the negative plate so there's a force of attraction. Work must be done on the capacitor to over come this force so that the positively charged of the dielectric is separate from the negative plate |
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State two assumptions about the motion of molecules in a gas |
Molecules move around radomly and collisions between molecules and the walls are elastic |
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Explain why the pressure inside a football increases when the temperature of air inside it increases when volume remains constant? |
Raise in temperature causes molecules to gain kinetic energy which means that there's more collissions with the inside of the football per second. This makes the rate of change of momentum greater which makes the force exerted by the molecules greater and therefore the pressure greater since pressure=F/A. |
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How does lenz's law predict the direction of the current in coil y? |
Lenz's law predicts that the induced current is going to be in the opposite direction to that which created it. This means that when the switch is closed current increases the flux through y. This means that current will flow anticlockwise to create opposing flux. When the switch is off the flux through y decreases since the current in x decreases which means that current flows clockwise to create flux to oppose the decrease |
