EducatorSharmin

    Physics Effect of Heat on Matter Chapter- 6 Q. 1. At the time of construction of a rail line why are small gaps kept in between two rails? Ans: To avoid bending of the rails due to its thermal expansion Q.2. Why do we feel comfort when wind is blown by fans over our sweating body? Ans: Evaporation prouces cooling Q.3. With the help of latent heat -  Ans:  Temperature of a body increases, state of a substance changes,           internal energy of a body increases Heat is a type of energy. The combined kinetic energy of molecules of a substance is called heat energy. The SI unit of heat is Joule (J). 1 Calorie (cal) = 4.2 Joule (J). The amount of heat energy required to increase the temperature of 1 gm of water by 1⁰C is called 1 Calorie.  The international unit of temperature is Kelvin (K). The property of a substance which changes with temperature and, measuring the change accurately, is called - Thermometric Property. The therm...

Hooke's Law   Physics            Scientist Robert Hooke expressed the relation between stress and strain by a law, which is - Hooke's Law: Within elastic limits stress is directly proportional to strain.                    Stress                            Q.1. What is strain?                       Ans: The relative change in length or shape which is made by applying a force from outside, is known as strain.                         Q.2. What is Buoyancy?                           Ans: Buoyancy is an upward force exerted by a fluid that opposes the weight of an immersed object.     Q.3. A weight of 10 kg is hung from a metal rod of 0.5 m len...