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About Arnav

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  • Favorite Area of Science
    Space time
  1. Sorry, but I haven't been taught about potential dividers yet. Yeah, I reckon in an actual circuit the number of resistors would be more than 1, as my case of "cell with 0 internal resistance and only one load" is very very ideal. So in a non-ideal case, even if we ignore the internal resistance of the source, the voltage measured by voltmeter would again come out to be less if its resistance is not very very high. I have uploaded 3 scenarios, one which is the actual case, one with low resistance voltmeter, and one with very high resistance voltmeter. I have ignored internal resistance of the cell. Couldn't upload the third case, but I know you guys get what I am trying to say
  2. A voltmeter has a very high resistance so that it doesn't draw a considerable amount of current from the circuit when connected in parallel. Lets say we have a circuit consisting of a single cell and a load of resistance R. Now a voltmeter is connected in parallel with a load of resistance R. If the resistance of the voltmeter will be low, then it will draw some current from the circuit , leading to an increased magnitude of current in the circuit than before( or we can say equivalent resistance of the combination would be less than before, leading to increased current). If the cell has an internal resistance r, then the voltage drop across r would be more than before hence the voltage across R, which the voltmeter is to measure, will be less. Even if we take another resistance in series with R, and ignore r, then the measurements will be same, i.e. wrong. But, now imagine that we take an ideal cell with internal resistance=0, and connect the resistance R with the voltmeter in parallel with it. Now, the measurement of the voltmeter will not be wrong even if its resistance is low, am I right ? Sorry if I couldn't explain my question, if anyone wants, then I can send some calculations to put up my statement.
  3. Thanks swansont for the paper, but I lost it at the caloric thing😅 Studiot, how did Avogadro conclude that the ratio of the volumes of two gases under similar conditions was equal to the ratio of their molecular weights? Sorry if I sound too dumb
  4. How did Avogadro 'actually' derive his law stating "equal volumes of gases under similar conditions of temperature and pressure contain same number of molecules" ? I am a 10th grader so I would appreciate a lucid and intuitive explain if the derivation involves higher concepts of science.
  5. Thank you for your reply studiot, but I couldn't follow the second last paragraph of your explanation, starting with Your book must have assumed.... You see guys, even here I am getting mixed answers, John says the data is insufficient and studiot says the question's fine.
  6. Here's a question, and my doubt is at the end of the question. I have been struggling with this doubt for quite long and have been receiving mixed opinions. A cell of emf 12 v supplies a current of 400 mA to an appliance. After some time the current reduces to 320 mA and the appliance stops working. Find the resistance of the appliance, the terminal voltage of the battery when the appliance stops working, and the internal resistance of the cell. In my book, the answer to this ques is given as follows: 1. Given, emf = 12 volt, I = 0.4 A Therefore Resistance of the appliance R = emf/ I = 12/0.4 = 30 ohm 2. Given , I' = 0.32 A Terminal voltage of battery V = I'R = 0.32*30 = 9.6 volt 3. From emf= V - v, v ( voltage drop) = emf-V= 12-9.6= 2.4 volt From v= I'r, r = v/I'= 2.4/0.32= 7.5 ohm ( internal resistance) My doubt is, in the 1st part, why isn't R= resistance of the appliance + internal resistance? Why is the internal resistance of the cell ignored in part 1?
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