Diversity In Living Organisms — Science STD 9 — Question

A plastic ball and a clay ball of equal masses, travelling in the same direction with equal speeds, strike against a vertical wall. From which ball does the wall receive a greater amount of momentum?

An element X has a valency of 4 whereas another element Y has a valency of 1. What will be the formula of the compound formed between X and Y?

Classify the following crops as Rabi and Kharif: Paddy, Wheat, black gram, cotton, gram and peas.

State whether the following statements are true or false:
Salt and water can be recovered from an aqueous salt solution by the process of evaporation.

Write the full forms of the following:
CNG

Explain why:
Air is used to inflate tyres.

What term is used to denote the change of velocity with time?

Give two examples of concentrates.

Name the gas which produces anode rays consisting of protons in the discharge tube experiment.