The method used to separate aluminium from a alumina is
electroplating
electrotyping
electrolysis
distillation
Correct Answer :
C. electrolysis
Related Questions
Echoes are produced by
the reflection of sound waves
the refraction of sound waves
the interference of sound waves
reverberation of sound waves
The stars that shine brightly then dimly and then brightly are known as
meteors
binaries
variable stars
bright stars
The planet that moves fastest around the sun is
Mars
Venus
Earth
Mercury
To get 5 images of a single object one should have two plane mirrors inclined at an angle of
72°
60°
36°
90°
The freezer in a refrigerator is placed near the top
to keep it away from the hot compressor which is near the bottom
because of convenience
so that it can cool the whole interior by setting up convection currents
to prevent too much cooling
A hunter on the ground wishes to shoot a bird on a tree at a distance with his rifle. He has to point the rifle
at the lower elevation than the bird
at a higher elevation than the bird
in the same direction as the bird
vertically upwards
The attraction of unlike molecules at the common surface is known as
adhesion
cohesion
surface tension
capillarity
A small bubble of air deep down in a lake rises up to the top of the lake. The volume of the bubble on coming up will
increase
decrease
will not change
first increase and then decrease
Which metal is used in storage batteries?
Copper
Lead
Tin
Iron
The velocity of sound in air
increases as the square root of the absolute temperature
decreases with temperature
is independent of temperature
None of these
Water kept in an earthen pot is less cool on rainy days than in summer because during the rainy days
the pores in the pot are closed
rain water stops oozing out from the pores
the water that oozes out does not evaporate quickly because of the large percentage of moisture in the air
surface of the pot becomes damp
At what temperature do the Fahrenheit and Kelvin scales give the same reading?
212°
32°
-40°
0°
A proton is
the ionised hydrogen molecule
the nucleus of helium atom
the nucleus of hydrogen atom
the positive counterpart of electron
We always see only one side of the moon because
the sun comes in between the earth and moon
the moon is stationary
the time taken by the moon to rotate on its axis is the same as the time taken by it to revolve round the earth
moon revolves round the sun
The loudness of a sound is determined by
Frequency
Amplitude
Speed
Wavelength
The device used to record the sound is
a microphone
a headphone
a phonograph
an amplifier
The attraction between similar molecules is called
inertia
adhesion
cohesion
friction
Solar radiation is preferred to other sources of energy because
it is practically inexhaustible
it is the cheapest form of energy
it does not cause pollution
All of the above
A man Jumping out of a moving train is thrown
forward
backward
sideways
None of the above
Which of the following apparatus is used in the electrolysis of water?
Voltmeter
Voltameter
Ammeter
Potentiometer
A boat loaded with rocks floats in the middle of a swimming pool. A man in the boat throws the rocks overboard. The level of water in the pool will
increase
decrease
remain the same
first decrease and then increase
The loudness of a sound is determined by
Frequency
Amplitude
Speed
Wavelength
It is difficult to bon potatoes at the top or a mountain because
the water available is hard
it is colder than at sea level
the potatoes become hard
the boiling point of water is lower at that height on account of low atmospheric pressure
Heat transfer
cools the body that transfers it
heats the body that absorbs the heat
may change the physical state of the substance
All the above
A tube light works on the principle of
chemical, heating and magnetic effects of electricity
discharge of electricity through gases
the action of ultraviolet radiation on certain fluorescent materials
Both (b) and (c) above
Nuclear fusion is a process in which
the atoms and molecules lose their identity
nucleus is split into fragments
the nuclear reaction between two light atomic nuclei results in the formation of a heavier nucleus with release of a large quantity of nuclear energy in the process
absorption of neutron by a nucleus
Which of the following rays has the highest penetrative power?
a -rays
� -rays
? -rays
X-rays
The planet that moves fastest around the sun is
Mars
Venus
Earth
Mercury
Pyrometers are instruments used
for measuring the velocity of wind
in the manufacture of fireworks
in finding the coefficient of apparent expansion of a liquid
for measuring high temperatures
The asteroids belt lies between the orbits of
Earth and Mars
Venus and Earth
Mars and Jupiter
Moon and Mars