During the refraction of light wavelength and speed change. Frequency is always a constant quantity.

(i) It is present only in troposphere. (ii) It is present in very small quantities in stratosphere. (iii)It can be beneficial or harmful, depending upon its location and concentration. (iv) It shields the surface of the earth from ultraviolet (UV) ...

Sodium and potassium react violently with the release of huge amount of heat. So the reaction is highly exothermic. Hydrogen gas which is produced during the reaction catches fire. Calcium reacts less violently with water. The heat evolved is not ...

Metals react with water to produce metal oxide and hydrogen gas. Metal oxides that are soluble in water, dissolve in water to form metal hydroxide.

Class 10 Science Terminal Exams MCQ Solutions Class X Science MCQ Extra Questions Answers 10th Science Terminal Exam Based MCQ Extra Questions Class 10th Science Session 2022-23