Sarahisme Posted May 25, 2005 Share Posted May 25, 2005 here are a quick to questions, how'd i do? Link to comment Share on other sites More sharing options...
Sarahisme Posted May 25, 2005 Author Share Posted May 25, 2005 my answer: e -Sarah Link to comment Share on other sites More sharing options...
swansont Posted May 25, 2005 Share Posted May 25, 2005 Explain why. Link to comment Share on other sites More sharing options...
Sarahisme Posted May 25, 2005 Author Share Posted May 25, 2005 this one i am not so sure about...or not confident enough to try and explain it Link to comment Share on other sites More sharing options...
Sarahisme Posted May 25, 2005 Author Share Posted May 25, 2005 i did for the other questions though Link to comment Share on other sites More sharing options...
Douglas Posted May 25, 2005 Share Posted May 25, 2005 The battery voltage is constant the instant the switch is closed the voltage on the capacitor is 0v thus, the voltage drop across the resistor is equal to the battery voltage since the cap blocks DC, one plate begins to charge. When the charge reaches the battery voltage the voltage drop across the resistor is 0v Link to comment Share on other sites More sharing options...
mezarashi Posted May 25, 2005 Share Posted May 25, 2005 I agree with (e) too Here are some mathematical aids. See for yourself which one is true Using the formal definitions introduced in electric circuits: (a) i = C dV/dt Cdv = int (i dt) CV = Q where C = capacitance, V = voltage across capacitor = Vcapacitor, Q = charge on capacitor. Note that Vcapacitor is always less than Vbattery, and so Q/C is always less than Vbattery. i = V/R (Ohm's Law) i = (Vbattery - Vcapacitor)/R i = (Vbattery - Q/C)/R (b) Voltage drop across resistor: delta V = Vbattery - Vcapacitator delta V = Vbattery - Q/C © i = (Vbattery - Q/C)/R (d) Q = charge on capacitor = charge across capacitor = Qcapacitor (e) delta V = Vbattery - Q/C Link to comment Share on other sites More sharing options...
Sarahisme Posted May 25, 2005 Author Share Posted May 25, 2005 any hints? pwease Link to comment Share on other sites More sharing options...
swansont Posted May 26, 2005 Share Posted May 26, 2005 any hints? pwease Douglas explained it. Link to comment Share on other sites More sharing options...
Sarahisme Posted May 26, 2005 Author Share Posted May 26, 2005 ok i think i understand it now, thanks guys Link to comment Share on other sites More sharing options...
Sarahisme Posted May 26, 2005 Author Share Posted May 26, 2005 wait a second there isnt more than one of those options that are correct are there? ie. e is the ONLY correct answer...?? right? cause i think it is... Link to comment Share on other sites More sharing options...
mezarashi Posted May 26, 2005 Share Posted May 26, 2005 Yes ^^ only e is true. Follow the arguments. See if the changing the variables in the equations for a, b, c, and d will make the assumptions in the questions hold true. Link to comment Share on other sites More sharing options...
Sarahisme Posted May 26, 2005 Author Share Posted May 26, 2005 yeah i thought so, just checking thankss mezarashi Link to comment Share on other sites More sharing options...
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