Friday, April 26, 2019

WBCS Polity and Constitution MCQs Prelims and Mains

WBCS Prelims and Mains MCQs on General Science (Chemistry) P7

Chemistry - 07

31. Fuse wire is made up of
(A) 63% tin, 37% aluminum
(B) 63% lead, 37% aluminum
(C) 63% tin, 37% Lead
(D) 63% lead, 37% tin.

Correct Answer: [D] 63% lead, 37% tin..
32. The energy of an electron in the first Bohr orbit is -13.6 eV. What will be its energy in the second Bohr orbit?
(A) -27.2 eV.
(B) -13.6 eV
(C) -6.8 eV
(D) -3.4 eV.

Correct Answer: [D] -3.4 eV..
33. The process by which the gas comes out of an L.P.G. Cylinder is called
(A) Pressure
(B) Ventilation
(C) Diffusion
(D) Effusion.

Correct Answer: [C] Diffusion.
34. Lightning discharges in air induce rain formation. This is because they cause
(A) The electrical discharge activate the H2O molecules
(B) They induce a photochemical reaction
(C) Nitrogen and oxygen of the air to combine
(D) Some gas molecules to ionize.

Correct Answer: [B] They induce a photochemical reaction.
35. Oxidation number of oxygen in superoxide is
(A) -1
(B) +2.
(C) 0
(D) -1/2.

Correct Answer: [D] -1/2..


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