# An ammeter of resistance 0.80Ω can measure currents upto 1 A . (i) What must be the shunt resistance to enable the ammeter to measure current upto 5A ? (ii) What is the combined resistance of the ammeter and the shunt?

1
by LaatiGola484

2015-09-15T04:27:31+05:30

### This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
We have to make the current flowing in the internal resistance 0.80 Ω to 1/5 th of the current flowing ie, of 5 A.

When 1 A flows through the internal resistance 0.80 Ω, the remaining 4 Amp current flows through the shunt resistance S.   Their currents are inversely proportional to their resistances, (they are in parallel)

so      0.80 Ω/ S  =  4 A /1 A
S = 0.2 Ω  = shunt resistance

Combined resistance of shunt and internal resistance:  0.8 * 0.2 / (0.8+0.2) = 0.16 Ohms

click on thanks button above please