Step 1: Water exhibits an anomalous expansion behavior between $0^\circ$C and $4^\circ$C. Unlike most substances, its density increases as it is heated from $0^\circ$C to $4^\circ$C, causing the volume to decrease.
Step 2: At exactly $4^\circ$C, water reaches its maximum density, meaning its volume is at a minimum.
Step 3: When heated beyond $4^\circ$C, water behaves normally, expanding as the temperature increases, leading to an increase in volume.
Step 4: Therefore, the correct answer is (A). \bigskip
A thin rod having a length of \(1 m\) and area of cross-section \(3 \times 10^{-6} m ^2\) is suspended vertically from one end. The rod is cooled from \(210^{\circ} C\) to \(160^{\circ} C\) After cooling, a mass \(M\) is attached at the lower end of the rod such that the length of rod again becomes \(1m\). Young's modulus and coefficient of linear expansion of the rod are \(2 \times 10^{11} N m ^{-2}\) and \(2 \times 10^{-5} K ^{-1}\), respectively. The value of \(M\) is ____ \(kg\). (Take \(g =10 \ m s ^{-2}\))
The general solution of the differential equation \( \frac{dy}{dx} = xy - 2x - 2y + 4 \) is: