school pa system

'A specified part of the universe which is under investigation is called the system'. The system is separated from the rest of the universe by a definite (real or imaginary) boundar..

A system, which can exchange energy but not mass with the surroundings is called a closed system. For example, boiling water in a closed steel vessel is an example of a closed system. The energy can be gained or lost (through the steel walls) but not matter. Simi..

A system, which can exchange matter as well as energy with the surroundings is called an open system. All reactions carried out in open containers are examples of open systems. Evaporation of water in a beaker or hot coffee in a cup represents an open system..

A method known as the Geneva system was suggested in 1892 by the International Chemical Congress at Geneva for naming organic compounds. Later the International Union of Chemistry at Liege (Belgium) developed it into IUPAC system of nomenclature in 1930. In 1958, the IUPAC..

Types of Circulatory System - Animals possess two type of circulatory system. They are a) Open type and b) Closed ty..

A system, which can exchange matter as well as energy with the surroundings is called an open system. For e.g., hot coffee in an open flask because it can gain or loose matter and energy with the surroundings. fig 4.1 - Example of open system..

A radian is the measure of an angle at the centre of a circle subtended by an arc, whose arc length is equal to the radius of the circl..

A system, which can exchange energy with the surroundings but not mass is called a closed system. For e.g., calcination of CaCO 3 taken in sealed bulb. On heating, CaCO 3 decomposes into CaO and CO 2 , however, CO 2 cannot escape and remains trapped in the bulb...

White Blood Corpuscles - The WBCs are larger in size than the RBCs but much lesser in number. They are different from the erythrocytes in the following aspects. a) They have no haemoglobin b) They are bigger in size c) They are nucleated and amoeboid d) They have a longer life span e) There ar..

The closed circulatory system can be represented as follows. Diagram showing inter-relationship between artery, vein and capillary The closed blood vascular system is a very well developed system This is so because, a) The organisms have a thick body wall to preve..