General Science Questions and Answers Part-8

1. In an atomic explosion, enormous energy is released which is due to
a) Conversion of chemical energy into heat energy
b) Conversion of mechanical energy into nuclear energy
c) Conversion of mass into energy
d) Conversion of neutrons into protons

Answer: c
Explanation: In an atomic explosion, enormous energy is released which is due to the conversion of mass into energy. Since most of the mass of ordinary objects resides in protons and neutrons, converting all the energy of ordinary matter into more useful energy requires that the protons and neutrons be converted to lighter particles, or particles with no rest-mass at all. Based on Einstein's equation E = mc2, the amount of energy added is relative to the mass gained by the proton multiplied by the speed of light squared. In other words, a lot of energy is converted into a relatively small amount of mass.

2. Isotopes are separated by:
a) Crystallisation
b) Sublimation
c) Distillation
d) Filtration

Answer: c
Explanation: Isotopes are separated by Distillation.

3. The wavelength of X-rays is of the order of
a) 10 micron
b) 1 angstrom
c) 1 cm
d) 1 m

Answer: b
Explanation: The wavelength of x-ray is 1 angstrom.

4. Mesons are found in
a) Laser beam
b) X-rays
c) Gamma rays
d) Cosmic rays

Answer: d
Explanation: Mesons are not produced by radioactive decay, but appear in nature only as short-lived products of very high-energy interactions in matter, between particles made of quarks. In cosmic ray interactions, for example, such particles are ordinary protons and neutrons. Mesons are hadronic subatomic particles composed of one quark and one anti-quark, bound together by the strong interaction. Because mesons are composed of sub-particles, they have a physical size, with a radius roughly one femtometre, which is about 2/3 the size of a proton or neutron. All mesons are unstable, with the longest-lived lasting for only a few hundredths of a microsecond. Charged mesons decay (sometimes through intermediate particles) to form electrons and neutrinos

5. Which radioactive pollutant has recently drawn to public, due to its occurrence in the building material?
a) Thorium
b) Radium
c) Plutonium
d) Radan

Answer: a
Explanation: Thorium radioactive pollutant has recently drawn attention of public due to its occurrence in the building material.
Thorium is a naturally-occurring, slightly radioactive metal discovered in 1828 by the Swedish chemist Jons Jakob Berzelius, who named it after Thor, the Norse god of thunder. It is found in small amounts in most rocks and soils, where it is about three times more abundant than uranium.
The alpha particles can travel only very short distances through most materials and cannot go through human skin.

6. The vast resources of unutilised natural gas can be used in the production of
a) Graphite
b) Synthetic petroleum
c) Fertilisers
d) Carbide

Answer: c
Explanation: The vast resources of unutilised natural gas can be used in the production of fertilisers.

7.Paper is manufactured by
a) Wood and resin
b) Wood, sodium and bleaching powder
c) Wood, calcium, hydrogen sulphide and resin
d) Wood and bleaching powder

Answer: c
Explanation:Paper is a thin sheet material produced by mechanically and/or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying.

8. Gypsum is added to cement clinker to
a) Increase the tensile strength of cement
b) Decrease the rate of setting of cement
c) Facilitate the formation of colloidal gel
d) Bind the particles of calcium silicate

Answer: a
Explanation: During cement manufacturing process upon cooling of clinker a small amount of gypsum is added during the final grinding process. Gypsum controls the setting of the cement and if not added the cement will set immediately leaving no time for concrete placing.

9. Soap is a mixture of sodium or potassium salts of
a) Dicarboxylic acids
b) Mono-carboxylic acids
c) Glycerol
d) Tricarboxylic acids

Answer: b
Explanation: Soaps are made from the sodium and potassium salts of long chain carboxylic acids.

10.The type of glass used in making lenses and prisms is
a) Jena glass
b) Soft glass
c) Pyrex glass
d) Flint glass

Answer: d
Explanation: In the optical glass industry, flint glass is any highly refractive lead-containing glass used to make lenses and prisms. Because it absorbs most ultraviolet light but comparatively little visible light, it is also used for telescope lenses.