GATE Questions

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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.

A bottle has a mouth from which we used to drink water or any juice. But it cannot smile.

A Soap.

Yes, it gets shrinks smaller every time we take a bath.

'Hypothesis' is a word that gives a brief explanation of the concepts based on the limited evidence. The word 'theory' is closest in meaning to it.

A Light-year is a distance that light travels in the vacuum in one Julian year (365.25 days).

The light-year is a unit of length used to express astronomical distances. It is about 9.5 trillion kilometers or 5.9 trillion miles. 

Let 'n' number of days it take to complete.

we know that sum of n number= n/2[2a+(n-1)d]
where a=20,d=1;
n/2[2x20+(n-1)1]=275
n[n+39]=550
n2 + 39n - 550 = 0
 n2+ 50n - 11n - 550 = 0
(n-11) (n-50) = 0
n-11 = 0;
n = 11(Days).