Question

The value of resistance of an unknown resistor is calculated using the formula `R = V//I ` where V and I are the readings of the voltmeter and the ammeter, respectivley. Consider the circuits below. The internal resistances of the voltmeter and the ammeter `(R_V and R_G, respectively)` are finite and nonzero.
,
Let `R_(A) and R_(B)` be the calculated values in the two cases A and B , respectively.
If the resistance of voltmeter is `R_(V) = 1k Omega` and the percentage error in the measurement of R (the value of R is nearly `10 Omega`)is
A. zero in both cases
B. non zero but equal in both cases
C. more in circuit A
D. more in circuit B

Answer 1

Correct Answer - D
`%` error in case A
`(R_(A)-R)/(R)xx100=((R_(V))/(R+R_(V))-1)xx100`
`=(-R)/(R+R_(V))xx100approx-1%` `%` error in case B
`(R_(B)-R)/(R)xx100=(R_(G))/(R)xx100approx100approx10%`