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.
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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

Options

A. zero in both cases
B. nonzero but equal in both cases
C. more in circuit A
D. more in circuit B

Answer

D

Explanation

d. `R_(A) = R_(A) = (R xx R_V)/(R+R_V) ltR`
`R_(B) = R+R_0 gtR`
(Tough) % error in case A.
`(R_(A)-R)/R xx 100 = (R_(V)/(R+R_(V)) -1) xx 100 `
`R/(R+R_(V)) xx 100 = - 1%`
Percentage error in case B
`(R_(B) - R)/R xx 100 = R_(G)/R xx 100 = 10%`
Hence, percentage error in circuit B is more than that in A.