Two groups A and B perform a similar experiment to measure t

Two groups A and B perform a similar experiment to measure the resistance of a wire. Both to use the following relation to calculate the value of the wire resistance in terms of the measured values of primary variables (R_0, alpha, and T) R = R_0 [1 + alpha(T - 20)] Group A got the following measurements: R_0 = 5 Ohm plusminus 0.5% alpha = 0.0035 degree C^-1 plusminus 1% T = 35 plusminus 1 degree C Group B got the following measurements: R_0 = 5 Ohm plusminus 0.7% alpha = 0.0035 degree C^-1 plusminus 0.8% T = 35 plusminus 0.5 degree C Which of the two groups will have a more accurate value of R. Which of the above primary variables affects the accuracy of R measurement most.

Solution

Ans:-

Consider positive value of the accuracy for both wire,

For Group A wire using values as,

R0= 5+0.5/100=5.005 ohm, alpha= 0.0035+1/100=0.0135, T=36 C

Now putting values in equations,

We get RA= 6.08608ohm

For wire RB= 5.89949 ohm

From answer we can say that wire B is more accurate than wire A.

Temparature is the primary variable on which accurac resistance of wire depends.