Which of the following wires expanded the least at 80^circ C A Brass A B Nickel B C Copper C D ) Aluminum

To determine which wire expanded the least at $80^{\circ }C$, we need to consider the coefficient of linear expansion for each material.<br /><br />The coefficient of linear expansion (α) is a measure of how much a material expands or contracts per degree change in temperature. The lower the coefficient, the less the material will expand or contract.<br /><br />Let's compare the coefficients of linear expansion for the given materials:<br /><br />A) Brass: α ≈ 19 x 10^-6 /°C<br />B) Nickel: α ≈ 13 x 10^-6 /°C<br />C) Copper: α ≈ 16.5 x 10^-6 /°C<br />D) Aluminum: α ≈ 23 x 10^-6 /°C<br /><br />Based on the coefficients, we can see that Nickel (B) has the lowest coefficient of linear expansion, which means it will expand the least at $80^{\circ }C$.<br /><br />Therefore, the correct answer is B) Nickel.