A potential difference of 4v connected to 4 uniform resistance wire of length 3m and cross section area 9×10⁻⁹m ,when a current of 0.2Ais flowing in a wire . <1> find resistivity of a wire. <2> vonductivity of a wire

Tunapewa:
Potential difference $V = 4 \text{ V}$
Current $I = 0.2 \text{ A}$

$$R = \frac{V}{I} = \frac{4 \text{ V}}{0.2 \text{ A}}$$ $$R = 20 \Omega$$

Tunapewa:
Upinzani $R = 20 \Omega$
Urefu wa waya $L = 3 \text{ m}$
Eneo la msalaba $A = 9 \times 10^{-9} \text{ m}^2$

$$\rho = \frac{R \times A}{L}$$ $$\rho = \frac{20 \Omega \times 9 \times 10^{-9} \text{ m}^2}{3 \text{ m}}$$ $$\rho = \frac{180 \times 10^{-9}}{3} \Omega \cdot \text{m}$$ $$\rho = 60 \times 10^{-9} \Omega \cdot \text{m}$$ $$\rho = 6.0 \times 10^{-8} \Omega \cdot \text{m}$$

Resistivity ya waya ni $\boxed{6.0 \times 10^{-8} \Omega \cdot \text{m}}$.

2. Conductivity ya waya.

Conductivity ni kinyume cha resistivity ($\sigma = \frac{1}{\rho}$).

$$\sigma = \frac{1}{6.0 \times 10^{-8} \Omega \cdot \text{m}}$$ $$\sigma = 0.1666... \times 10^8 \text{ S/m}$$ $$\sigma = 1.67 \times 10^7 \text{ S/m}$$

Conductivity ya waya ni $\boxed{1.67 \times 10^7 \text{ S/m}}$.