Awire of nichrome (a nickel-chromium-iron alloy commonly used in heating elements) is 1.3 m long and 1.6 mm2 in cross-sectional area. it carries a current of 3.2 a when a 2.0 v potential difference is applied between its ends. calculate the conductivity σ of nichrome. /ω · m

1.3 *10^6 Ω*m

Explanation: In order to explain this problem we have to use the following expression for the resistence:

R=L/(σ*A) where L and A are the length and teh area for the wire, respectively. σ is the conductivity of teh Nichrome.

Then, from mteh OHM law we have V=R*I so R=V/I=2/3.2=0.625 Ω

Finally we have:

σ=L/(R*A)=1.3/(0.625*1.6*10^-6)=1.3*10^6 Ω*m

convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.