Q is directly proportional to v but v is not directly proportional to Q why
Answers
Explanation:
says that if you have a test charge Q, and you want to move it from place-1 to place-2, and it takes an amount of work W to do it, then the potential (voltage) at place-2 is higher than that at place-1 by an amount V. The equation may make it may look like V depends on Q, but it does not: if you double the charge, it takes twice as much work to move it, and the V remains the same. The potential is a function of the pre-existing electric field, and the equation simply tells you how much work it takes to move a given amount of charge around in that field.
Q=CV says that the potential difference across a capacitor is proportional to the amount of charge on each plate of the capacitor, and defines the capacitance, C as the constant of proportionality. It is much less general than the first equation: there are many situations where the concept of capacitance is not applicable. Moreover, the charge referred to in the equation is the charge that produces the field, not one that experiences it.