When water is cooled from 4�C to 2�C its density
increases
decreases
remains the same
first increases then decreases
Correct Answer :
B. decreases
Related Questions
Ultrasonic waves are used
in medical and surgical diagnosis
in testing the quality of the linings and pads used in vehicles and aircraft brakes
to clean surgical instruments, jewellery and similar articles
All the above
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 star nearest to the sun is
Proxima Centauri
Sirius
Aldebaran
Vega
The orbit of Venus lies between those of
Mercury and Earth
Earth and Mars
Mars and Saturn
Mars and Jupiter
When a satellite la In a geostationary orbit the force keeping it in orbit Is
zero
the centrifugal force
reaction due to steady burning of fuel
the gravitational pull on the body by the earth is the weight of the body which provides the centripetal force
The first Indian Satellite launched from a Russian Cosmodrome on April 16, 1975 was named
Bhaskara
Insat I-A
Aryabhatta
SLV-l
The barometer was invented by
Michael Faraday
Torricelli
Thomas Alva Edison
Benjamin Franklin
The function of a ruse wire is
to stabilise the voltage
to decrease the current supply
to increase the current supply
to prevent an unduly high current from passing through a circuit
We see the flash of lightning before hearing the thunder because
light travels very much faster than sound
sound travels faster than light
lightning occurs nearer than thunder
both travel at the same speed
Air pressure is usually highest when the air is
warm and moist
cool and dry
warm and dry
cool and moist
A device used in a ship for the purpose of measuring the depth of the sea is
an altimeter
a fathometer
a hydrometer
a sonometer
The shadow below a tree has bright spots in it because
light comes through circular gaps between the leaves
the leaves are circular
the rays bend to form circular spots
the gaps between the leaves act as pin holes
Before the invention of geostationary satellites, television stations could not transmit their programmes to far off places because
these signals are electromagnetic in nature
these are not electromagnetic in nature
their wavelength is very large
they are not reflected by the ionosphere but pass through it
Isotones are species of atoms containing
same number of protons but different number of neutrons
same number of neutrons but different number of protons
the same total number of protons and neutrons
same number of protons and different number of electrons
Atoms which have the same atomic number but different mass numbers are called
isobars
isomers
isotones
isotopes
The escape velocity of a satellite projected from the surface of the earth is independent of
the mass of earth
the mass of the satellite
the radius of the earth
gravitation of the earth
The property of a fluid by which it resists relative motion within itself is known as
cohesive force
surface tension
diffusion
viscosity
Cyclotron is an apparatus used
as an accelerator for imparting energies to charged particles of atomic magnitudes
to reduce the charge on a particle
to produce intense magnetic field
to produce intense electrical field
Why is nuclear fusion also known as thermonuclear reaction?
Fusion converts nuclear energy into heat
Fusion demands conditions of extremely high temperature to produce it
Fusion produces large amount of heat
Fusion reactions takes place in the sun
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
The earth's nearest neighbour in space is
the Sun
the Moon
the Venus
the Mars
Light from the sun reaches the earth in
2 minutes
4 minutes
12 minutes
8 minutes
Fish and other aquatic creatures can live inside a deep frozen pond because
fish are cold-blooded animals
ice is a bad conductor of heat
there will always be water just beneath the ice level
they can adapt themselves to live in ice
The overhead wires supported by high towers in the grid system carry
alternating current of very high frequency
alternating current of very high voltage
a very large direct current
a high voltage direct current
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
The principle of equivalence of mass and energy was established by
Dalton
Rutherford
Einstein
Planck
The asteroids belt lies between the orbits of
Earth and Mars
Venus and Earth
Mars and Jupiter
Moon and Mars
At what temperature do the Fahrenheit and Kelvin scales give the same reading?
212°
32°
-40°
0°
The orbit of Venus lies between those of
Mercury and Earth
Earth and Mars
Mars and Saturn
Mars and Jupiter
Why is it cool near an open pond on a hot summer day?
Evaporation at the surface causes cooling
The heat obsorbed at the surface is passed on to the bottom
Because of impurity in the water
Because of convection currents set up inside water