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Plzzz guys answer it if uh know25.) A voltmeter with resistance 2500 ohm -indicates avoltage of 125V in the circuit shown in figure.What is the series resistance to be connected tovoltmeter so that it indicates 100V? Consider idealbattery :-(1) 625 ohm(2) 120 ohm(3) 550 ohm(4) Data are insufficient |
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Answer» Answer: THE ANSWER TO THIS QUESTION IS 4) DATA INSUFFICIENT Explanation: GIVEN: PARAMETER INITIALLY FINALLY VOLTAGE 125 V 100 V CURRENT 0.05 A UNKNOWN RESISTANCE 2500 OHM 2500+x Where x is the resistance to be ADDED in series. If we ASSUME that the battery is ideal and hence that the current is not UNKNOWN but is the same as in case 1 and batteries capacity is constant that is not at all possible by "OHMS LAW" as V = I×R If the resistance is in series it increases and becomes 2500+x therefore putting I constant V would increase but not decrease hence second case current should be mentioned . Only if current is taken same and, Assuming parallel CONNECTION of resistance with volt meter this can be solved as the resultant resistance is LESS than actual. Hence proved that the option is d) DATA IS INSUFFICIENT |
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