Question

the resistance of a metal is given by r=v/i,where v is the potential difference and i is the current in a circuit the potential difference across the resistance is V=(10±0.5)V and current in resistance, I=(2±0.2)A

Answer 1

R = V/I

V =( 10 ±0.5) v

I = (2 ± 0.2)A

R = 10/2 = 5 ohm

V= IR
differentiate
dV = idR + Rdi

divide by ( IR) both sides
dv/IR = idR/IR + Rdi/iR

dV/V = dR/R + di/i

so, average error

±∆V/V = ±∆R/R ± ∆I/I

for maximum error in R

∆R/R = ∆V/V + ∆I/I

∆R/5 = 0.5/10 + 0.2/2

∆R = 0.25 + 0.5 = 0.75

so, Ract = ( R ±∆R ) = (5 ±0.75) ohm