GATE Questions

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Processes that require or give off heat will be limited to changes of state, known as phase changes, and changes in chemical constitution, or chemical reactions. Changes of state involve a solid melting, a liquid freezing, a liquid boiling or a gas condensing.

An exothermic process is one that gives off heat, which is transferred to the surroundings. An endothermic process is a reaction which heat has to be supplied to the system from the surroundings.

Here in all the given options, heat is taken away from them to change there phase. 

Liquid to Solid --- Freezing

Gas to Liquid --- Condensation

Gas to Solid --- Deposition 

are all examples of exothermic processes.

Radioactive decay is likely to occur when the nuclei of an atom doesn't have enough binding energy to hold the nucleus together due to excess of rotons or nutrons in it.

Spleen is called as the graveyard of RBC Red Blood Cells where they are selectively destroyed/recycled by macrophages.

False. Cube is not a Polygon.

Because polygon is a two dimensional figure and can be drawn on a flat surface whereas Cube is three dimensional figure and cannot be drawn on a flat surface.

Africa - 54 countries

South America - 12 countries

Antarctica - 0 countries

Europe - 43 countries.

Hence, Antarctica continent has the least countries.

In thermodynamics, deposition is a phase transition in which gases are directly transformed to solids without converting to liquids first.

For example, watervapour is directly changed to ice without first becoming to liquid water. In this process, heat is released making the process exothermic process.

Cost price = Rs. 30

Selling price = Rs. 50

Gain = Rs. 20

Profit % = Gain/cost price x 100 = 20/50 x 100 = 40%

Conditions suitable for the formation of a tornado develop when varying temperatures and humidity come together and form thunderclouds. This refers to the presence of warm and moist condition in the lower atmosphere and cold and dry conditions in the upper atmosphere. The place where these varying masses of air meet is known as the dry-line. Such conditions, which are suitable for the formation of a tornado, are most often observed just before a low pressure system develops.

Once the ideal conditions occur, the warm air tries to rise in the atmosphere, while the cold air blocks it. This makes the air in between rotate horizontally. In the meanwhile, the land is heated by the Sun, and hence, the air near the ground becomes warm and starts rising. Continuous fueling by the heat energy from the Sun ensures that the warm air has an upper hand over cold air. As a result of this, the cold air at the top starts sinking and the warm air below starts rising in a spinning motion. As the amount of warm air increases, the formation gains height and becomes intense. The intensity of these devastating tornadoes is such that they can clear off anything that comes in their path.