please answer this :

Question

A certain ammeter has an internal resistance of 1  and a range from 0 to 50 mA. To make

its range from 0 to 5 A, use:

A) a series resistance of 99 

B) an extremely large (say 106 ) series resistance

C) a resistance of 99  in parallel

D) a resistance of 1/99  in parallel

E) a resistance of 1/1000  in parallel

Answer 1

So this problem is best solved with the equation I = V/R. With a resistance of 1 ohm and a 50 mA current the voltage supply has to be something specific. If we solve the above equation we will see that the V = (50*10^(-3) A)*(1 ohm) = 50*10^(-3) V or 50 mV.

You would then change the resistance to achieve a max current of 5 A. Using the equation once again we solve for resistance and get R = V/I with V = 50*10^(-3) V and I = 5 A you should get something like 10 milliohms.

Once you have that, ask yourself how you could create a 10 milliohm resistance with a 1 ohm resistor and the multiple choice options availlable.

I can't give you the answer but you should be able to take it from here.