Question

Dimensions of a block are 1 cm× 1 cm× 100 cm. If specific resistance of its material is 3 × 10^–7ohm-m, then the resistance between it’s opposite rectangular faces is

• A. 3 × 10^–9ohm
• B. 3 × 10^–7ohm
• C. 3 × 10^–5ohm
• D. 3 × 10^–3ohm

Answer 1

Answer: (B)

3 × 10^–7ohm

Answer 2

Length l = 1 cm $= 10^{- 2}m$

Area of cross-section A = 1 cm × 100 cm

= 100 cm² = 10^–2 m²

Resistance R = 3 × 10^–7 $\times \frac{10^{- 2}}{10^{- 2}}$= 3 × 10^–7 Ω