PhysicsKund Physics class 9 to 12 NCERT, JEE - NEET

 Object : To establish the relation between the loss in weight of a solid fully immersed in (i) Tap water (ii) Strongly salty water , with the weight of water displaced by it by taking two different solid. Apparatus : Spring balance , steel or brass Bob , graduated measuring cylinder , thread , water , clamp stand and a Eureka can ( a glass or metallic container with a spout. Theory : Archimede's principle states that when an object is immersed wholly or partially in a liquid , it experiences an upward force which is equal to the weight of the liquid displaced by it. Apparent loss of weight of solid in water = weight of water displaced by the solid. Diagram :  Observation :  Weight of the bob ( made of steel or brass ) in air , W1 = ........ gmt. Weight of the bob when dipped in water , W2 = ....... gwt Apparent loss of weight of bob in water = W1 - W2 = ...... gwt Density of water at 4°C ( From tables ) = 1 g/cm3 Volume of water collected in the measuring cylinder , V = ...

Object : To verify the laws of Reflection of sound . Apparatus : Two metallic or cardboard tubes , stopwatch, Drawing board , plastic screen , protractor , chalk piece and a pencil. Theory : When sound is incident on wood , brick or a plaster wall , it returns back. The returning back of sound after striking a hard surface is called reflection of sound. Sound waves obey the laws of Reflection which are as follows :  1. The angle of incidence is equal to the angle of reflection. 2. Incident wave , reflected wave and the normal lie in the same plane. Diagram :  Observations :  Result : 1. Angle of incident sound wave = Angle of reflected sound wave. 2. Sound wave , normal and the reflected sound all lie in same plane. Precautions:   1. Careful measurement of angle should be done by using protractor. 2. Table top should be horizontal and the wooden board should be vertically placed. 3. The stopwatch should be placed near the end of tube placed on the left-hand side. 4...