Using three different voltmeters a group of students measured the same emf sourc
ID: 2304332 • Letter: U
Question
Using three different voltmeters a group of students measured the same emf source. Vi measured 1.52 v, V2 measured 1.43 v and V3 measured 1.35 v which voltmeter draws the most current from the emf source. C)? D) they all draw the same amount of current U19Q2 A standard cell with an emf of 1.018 volts when placed in a potentiometer circuit was found to have an arbitrary length L of 41.3. An unknown cell is then placed in the circuit and a decade box set to 450 ohms is in parallel with the unknown cell. The circuit was adjusted to a null and the arbitrary length of the unknown cell with this load was found to be Lunk-58.8. What is the terminal voltage VT? A) 0.70 v B) 1.45 v C) 1.42 v D) 0.715 v U19P1Explanation / Answer
If we are using the same emf source then the resistance of the emf source will be same irrespective of different voltmeters.
Using Ohm's law-
V=I (R1 + R2)
Say R1 - resistance of emf source
R2 - resistance of voltmeter
where I is the current flowing .
In our problem we are using 1 emf source so R1 will be same but for different voltmeters, their resistances will be different so in our problem R2 is changing that's why we are getting different voltages but it doesn't mean that different voltmeters are drawing different current.
Thus all voltmeters will draw same current from a single emf source.
One question can be answered at a time.plz don't thumb down bcoz of this reason.Thanks....
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