An ammeter of resistance 0.81 ohm reads up to 1 A. The value of the required shunt to increase the range to 10 A is

To increase the range of the ammeter from 1 A to 10 A, a shunt resistor is required. The shunt resistor is connected in parallel with the ammeter to divert some of the current away from it.

To calculate the value of the required shunt resistor, we can use the formula:

Rs = (Rm / Im) - Rm

Where Rs is the resistance of the shunt resistor, Rm is the resistance of the ammeter, and Im is the maximum current that the ammeter can read.

Given that the resistance of the ammeter is 0.81 ohm and it reads up to 1 A, we can substitute these values into the formula:

Rs = (0.81 ohm / 1 A) - 0.81 ohm

Rs = 0.81 ohm - 0.81 ohm

Rs = 0 ohm

Since the calculated resistance of the shunt resistor is 0 ohm, it means that no shunt resistor is required to increase the range of the ammeter to 10 A.