Good conductor of electricity is (1) dry air (2) paper (3) kerosene (4) graphite Answer: (4) Graphite has a tendency to behave very much like metal because the carbon molecules arrange themselves into a lattice structure. The crystal lattice is the same orientation that metal forms, and it allows the free movement of electrons, making it … Read more
If the length of a simple pendulum is halved then its period of oscillation is (1) doubled (2) halved (3) increased by a factor of 2 (4) decreased by a factor of 2 Answer: (4) The time period ‘T’ of a simple pendulum is given by T = 2πsqrt(l/g), where l is the length and g … Read more
Gamma rays can cause (1) genemutation (2) sneezing (3) burning (4) fever Answer: (1) In molecular biology and genetics, mutations are accidental changes in a genomic sequence of DNA: the DNA sequence of a cell’s genome or the DNA or RNA sequence in some viruses. These random sequences can be defined as sudden and spontaneous changes … Read more
When the barometer reading dips suddenly, it is an indication of (1) Hot weather (2) Calm weather (3) Storm (4) Dry weather Answer: (3) Sudden and great fluctuations of the barometer at any time of the year indicate unsettled weather for several days, perhaps a fortnight. If the barometer falls two or three-tenths of an inch … Read more
Wollen clothes keep the body warm because (1) Wool increases the temperature of the body (2) Wool is a bad conductor (3) Wool absorbs radiant heat from outer objects (4) Wool rejects heat from the outer objects Answer: (2) It is just because woollen clothes have fibres and between those fibres air is trapped which reduces … Read more
The source of the Sun’s energy is the process of (1) Photoelectric emission (2) Nuclear fission (3) Nuclear fusion (4) Thermionic emission Answer: (3) Nuclear fusion is a nuclear reaction in which two or more atomic nuclei join together, or “fuse”, to form a single heavier nucleus. During this process, the matter is not conserved because … Read more
Why are we able to hear short wave broadcasts better than longwave broadcasts? (1) Short waves are more energetic than long waves. (2) Short waves are unaffected by atmospheric disturbances. (3) Short wave broadcasts are made by nearby radio stations. (4) By convention, short waves are meant for long distances, whereas long waves are reserved … Read more
The fundamental scientific principle in the operation of the battery is (1) acid-base interaction (2) dialysis (3) dissociation of electrolytes (4) oxidation-reduction Answer: (3) The electrolyte consists of a solvent (water, an organic liquid, or even a solid) and one or more chemicals that dissociate into ions in the solvent. These ions serve to deliver electrons … Read more
Which of the following is used for regulated electric supply? (1) Zener diode (2) Junction diode (3) Gun diode (4) Tunnel diode Answer: (1) The Zener diode is like a general-purpose signal diode. When based in the forward direction it behaves just like a normal signal diode, but when a reverse voltage is applied to it, … Read more
Tungsten is used for the manufacture of the filament of an electric bulb, because (1) It is a good conductor (2) It is economical (3) It is malleable (4) It has a very high melting point Answer: (4) Tungsten is used because it has the highest melting point of all the metallic elements. It melts at … Read more