GATE Questions

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The part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life is called Biosphere.

Cosmology is the scientific study of the large scale properties of the universe as a whole. It endeavors to use the scientific method to understand the origin, evolution and ultimate fate of the entire Universe.

Depending on the outcome of the observations, the theories will need to be abandoned, revised or extended to accommodate the data. The prevailing theory about the origin and evolution of our Universe is the so-called Big Bang theory.

In an algebraic expression, like terms are terms that contain the same variables raised to the same powers. Calculating x-squared plus x-squared is a matter of combining like terms. 

Now x^2 + x^2 = 2x^2

Hence, x-squared plus x-squared is equal to 2 times x squared.

The Doppler effect or Doppler shift is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. 

Maglev trains are used in Japan, South Korea and China only.

Maglev derived from magnetic levitation using the principle of magnetic repulsion is a system of train transportation that uses two sets of magnets, one set to repel and push the train up off the track as in levitation then another set to move the 'floating train' ahead at great speed taking advantage of no friction. Maglev trains are therefore quieter and smoother than conventional trains, and have the potential for much higher speeds

Despite over a century of research and development, maglev transport systems are in operation in just three countries Japan, South Korea and China.

Hence Maglev -- Magnetic-levitation.

Ideal Gas Law ::

The Combined gas law or General Gas Equation is obtained by combining Boyle's Law, Charles' Law, and Gay-Lussac's Law. It shows the relationship between the pressure, volume, and temperature for a fixed mass (quantity) of gas:

P1V1T1 = P2V2T2

Hence, the Boyle's law P1V1 = P2T2, relates to ideal gas equation.

In chemistry, a metal is an element that readily forms positive ions (cations) and has metallic bonds. Metals are opaque, lustrous elements that are good conductors of heat and electricity. Most metals are malleable and ductile and are, in general, denser than the other elemental substances.

Examples of metals are aluminium, copper, iron, tin, gold, lead, silver, titanium, uranium, and zinc.

Here Se - Selenium is an element but is not a metal, S - Sulphur is not a metal and I - Iodine is also not a metal.

Hence, Zn - Zinc is the only metal in the given options.

Stars twinkle because they’re so far away from Earth that when light from the stars passes through the atmosphere, it is bent countless times due to refraction, making it look like as if they were blinking. The sun and other planets doesn’t twinkle because it’s too close to Earth compared to other stars.