Among the following, in which material the speed of sound is highest? (at 25^oC)

Aliminium

The correct answer is option 4. Aluminium.

Among the materials listed, in which the speed of sound is highest at 25°C is Aluminium.

In general, the speed of sound in a material depends on factors such as the material's density, elasticity, and temperature. At room temperature (25°C), aluminum typically has a higher speed of sound compared to other metals like nickel, steel, and iron. This is because aluminum is less dense and has a higher elasticity, allowing sound waves to travel faster through it.