Friday, April 26, 2019

WBCS Polity and Constitution MCQs Prelims and Mains

General Science (Chemistry) Previous Years Question of WBCS Prelims P4

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.

36. Particles which can be added to the nucleus of an atom without changing chemical properties are called
(A) Electron
(B) Particle
(C) Neutron
(D) Proton
Correct Answer: [C] Neutron.

37. Spectral lines of the hydrogen atom corresponding to emissions in the ultraviolet region is
(A) Brackett series
(B) Paschen series
(C) Lyman series
(D) Balmer series
Correct Answer: [C] Lyman series.

38. Ten liters of water makes about
(A) 9 liters of solid ice
(B) 10 liters of solid ice
(C) 11 liters of solid ice
(D) 15 liters of solid ice
Correct Answer: [C] 11 liters of solid ice.

39. In the solar spectrum, Fraunhofer lines are seen in the sodium D wavelength. This proves
(A) There is no sodium is the sun's interior
(B) There is sodium in the solar atmosphere
(C) There is no sodium in the sun
(D) There is no sodium in the atmosphere
Correct Answer: [B] There is sodium in the solar atmosphere.

40. Which one of the following is a thermoplastic polymer?
(B) Bakelite
(C) Rubber
(D) Nylon
Correct Answer: [D] Nylon.


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