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

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Page 4

164331. 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

D

Correct Answer: D. 63% lead, 37% tin

164432. 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

D

Correct Answer: D. -3.4 eV

164533. The process by which the gas comes out of an L.P.G. Cylinder is called

A

Pressure

B

Ventilation

C

Diffusion

D

Effusion

C

Correct Answer: C. Diffusion

164634. 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

B

Correct Answer: B. They induce a photochemical reaction

164735. Oxidation number of oxygen in superoxide is

A

-1

B

+2

C

0

D

-1/2

D

Correct Answer: D. -1/2

164836. 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

C

Correct Answer: C. Neutron

164937. 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

C

Correct Answer: C. Lyman series

165038. 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

C

Correct Answer: C. 11 liters of solid ice

165139. 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

B

Correct Answer: B. There is sodium in the solar atmosphere

165240. Which one of the following is a thermoplastic polymer?

A

PVC

B

Bakelite

C

Rubber

D

Nylon

A

Correct Answer: A. PVC
Explanation: A thermoplastic is a polymer that becomes pliable or moldable above a specific temperature and returns to a solid state upon cooling. These are the linear or slightly branched long chain molecules. For examples, PVC, polystyrene, nylon,polyethylene etc.

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