Q35 of 805 Page 180

How will you infer with the help of an experiment that the same current flows through every part of the circuit containing three resistances in series connected to a battery?

OR


Find out the following in the electric circuit given in the Figure.



(a) Effective resistance of two 8 Ω resistors in combination.


(b) Current flowing through 4 Ω resistor.


(c) Potential difference across 4 Ω resistor.


(d) Power dissipated by 4 Ω resistor.


(e) Difference in ammeter readings, if any.


In the above figure three resistors R1, R2, R3 are connected in series to a battery. An ammeter is connected between Points X and Y and let the reading be I. Ammeter is removed and connected between points B and C and the reading obtained is suppose I1. Similarly it is connected between D and E, reading is I2. Between F and Y reading is I3. It is observed that I = I1 = I2 = I3.


So it can be concluded that the same current flows through every part of the circuit containing three resistances in series connected to a battery.


OR


a. Effective resistance of two 8 Ω resistors in parallel combination


1/Rp = 1/8 + 1/8


1/Rp = 2/8


Rp = 4 ohm.


b. Current through 4 ohm resistor


I = V/R


Total resistance = 4 + 4


= 8 ohm


I = 8/8


= 1 A


c. V= IR


So potential difference across 4 ohm resistor = 1x4 = 4 V


d. Power dissipated = I2R


= 124


= 4 W


e. No, difference in readings as they are connected in series so same amount of current will pass through both of the ammeters.


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