One wire has a cross-sectional area of 1,250 circular mils and a resistance of 7 ohms. a second piece of wire, identical except for cross-sectional area, has a resistance of 10 ohms. determine what the cross-sectional area of this second wire is. (cross-sectional area and resistance are inversely proportional.)

As we know that resistance of the wire depends upon the area, length and its material

its formula is given by

so from above we can say that

Since all other parameters are same except area of the wire so we can say

So area of 2nd wire is less than the first wire and its magnitude is 875 circular mils.

b.a device that inputs heat into a cool object