Conductance

The graph shows the relationship between resistivity and temperature . For most materials, resistivity increases with temperature, but the rate of change varies depending on the material. - Material X shows a steep increase in resistivity with temperature, which is characteristic of nichrome (a metal with a high positive temperature coefficient of resistance). - Material Y shows a relatively moderate increase in resistivity, which is characteristic of copper (a metal with a lower positive temperature coefficient of resistance). - Material Z shows a small decrease in resistivity with temperature, which is characteristic of a semiconductor (which has a negative temperature coefficient of resistance). Thus, the materials are identified as: - X = nichrome, Y = copper, Z = semiconductor.

The nuclear force between nucleons is attractive at short distances, typically less than about 0.8 fm (femtometers), and it becomes repulsive at very short distances. This is because at distances smaller than 0.8 fm, the nuclear force overcomes the attraction, causing a repulsive effect. So, the statement "Nuclear force becomes attractive for nucleon distances larger than 0.8 fm" is incorrect. In reality, the nuclear force becomes repulsive at distances smaller than 0.8 fm and remains attractive only at short ranges. Thus, the correct answer is option (3).