Three resistances AB, BC, CD are joined in series and placed across the terminals of a galvanometer. The resistance of the galvanometer is 15 ohm and it gives full scale deflection for a current of 5 milliampere. Find the value of each of the resistances so that the instrument will serve as a multi-range ammeter, using external connections A and B for the 0-1 ampere range, to A and C for the range 0-0.1 ampere, and to A and D for the range 0-10milliampere.

I assume this needs some kind of simultaneous equation solving, but I can't figure it out!


closed as too localized by David Z May 30 '11 at 23:52

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  • $\begingroup$ Look up meaning of Galvanometer! $\endgroup$ – Georg May 30 '11 at 9:27
  • $\begingroup$ I'm not sure what you mean, I know what a galvanometer is, that isn't the question. $\endgroup$ – MathsStudent May 30 '11 at 9:29
  • $\begingroup$ I suggest you take a look at our homework policy-in-making: meta.physics.stackexchange.com/questions/714/… $\endgroup$ – David Z May 30 '11 at 23:54