Two wires A and B of same material and same mass have radius 2r and r. If resistance of wire A is 34 Ω then resistance of B will be

R=ρ lA and mass m - volume (V) x density (Al) dSince wires have same material so ρ and d is same for both.Also they have same mass ⇒ Al = constant⇒l∝lA⇒ R1R2 = l1l2 ×  A2A1 = A2A12 =  r2r14⇒ 34R2 =r2r4⇒ R2 = 544 Ω