False – outer zone is the hottest zone of a flame. The substances that vaporize while burning produces the flame. Flame is defined as the... View Article
(c) In vessel The rate of evaporation increases with the increase in surface area and wind speed. The surface areas of vessel C,A and D are... View Article
c) Iron Iron is a nutrient that is not available in fertilizers. Fertilizers are chemical substances supplied to the crops to increase their... View Article
Hydrogen gas is considered as the cleanest fuel because when hydrogen burns in air, it produces nothing but water vapour. It is therefore the... View Article
The process of domestication of animals and their rearing is known as animal husbandry. This process is used to increase the livestock of animals... View Article
Buccal Cavity: It is the entry site for the food to the digestive system. Food is breakdown into simpler molecules by mastication in the buccal... View Article
d) Polythene bag Polythene bags are not involved in soil formation. However, plastic bags are threat to environment, because these bags are... View Article
c) Tracheids Gymnosperms do not have vessels in their xylem. Water conducting tissues present in them are tracheids. They do not produce... View Article
This phenomenon of change of a liquid into vapours at any temperature below its boiling point is called evaporation. Evaporation is a phase... View Article
The substances which have very low ignition temperature and can easily catch fire with a flame are called Inflammable substances. Inflammable... View Article
Hoe It is one of the oldest tools of agriculture, a digging implement consisting of a blade set at right angles to a long handle. A hoe is a... View Article
In the environment, the percentage of the gases like oxygen, nitrogen and carbon dioxide is maintained by their cyclic flow. The oxygen cycle,... View Article
a) Echinodermata The body wall of Echinodermata is covered with spiny, hard, calcareous (calcium carbonate) plates (ossicles) that form a rigid... View Article
If humidity is high, then air is already saturated with water vapours, i.e., it has a lot of water vapours. Therefore, it will not take more... View Article
Voice becomes thin Breasts enlarge Hips become rounded Hairs grow under the armpit and in the pubic area Most girls gain weight (which is... View Article
(a) Cuticle Cuticle is a protective, hydrophobia waxy covering produced by epidermal cells of leaves, young shoots and other aerial parts. It... View Article
(a) chlorophyll The green colour of leaves is due to the presence of the pigment Chlorophyll. Chlorophyll is important in photosynthesis,... View Article
Three essential requirements are: Fuel Air Heat to acquire the ignition temperature A fire extinguisher is useful in controlling the fire in... View Article
True. Greater the calorific value, better is the fuel. The higher heating value (HHV) (or gross energy or upper heating value or gross calorific... View Article
True. Alcohol, CNG [Compressed Natural Gas] and LPG [Liquified Petroleum Gas] burn on ignition. So, these three elements are inflammable... View Article
