Boyle's law states that at constant temperature, the pressure of a fixed mass of gas is: MCQ with Answer and Explanation

Explanation:
The reactivity of metals with water depends on their position in the reactivity series. Sodium and potassium are highly reactive alkali metals that react vigorously and exothermically with cold water to form hydroxides and hydrogen gas. Iron reacts only with steam, while copper and silver do not react with water.

Explanation:
J.J. Thomson proposed the 'Plum Pudding' model in 1904 after discovering the electron. He envisioned the atom as a sphere of positive charge with negatively charged electrons embedded within it, like plums in a pudding. This was later disproved by Rutherford's gold foil experiment.

Explanation:
Radioactive decay emits alpha, beta, and gamma rays. Alpha particles are heavy and positively charged, stopped by paper. Beta particles are lighter, stopped by aluminum. Gamma rays are high-energy electromagnetic photons with no mass or charge, giving them the highest penetrating power; they require thick lead or concrete to be significantly attenuated.