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
When a charged rod is brought near a collection of small pith balls, the balls
will jump rapidly up and down for a short time
will remain unaffected
Both (a) and (b) above
It will produce electric shock
In a microphone
sound energy is converted into electrical energy
electrical energy is converted into sound energy
sound energy is converted into mechanical energy
mechanical energy is converted into sound energy
The velocity of sound in air increases with
the rise of temperature
rise of its frequency
decrease in humidity
fall of temperature
Primary colours are
colours of the rainbow
colours in the spectrum of white light
colours which cannot be produced by mixing other colours
colours found in nature
A piece of ice is Boating In water kept in a beaker. When all the ice melts the level of water will
first rise and then fall
fall
remain the same
rise
A boy is swinging a ball attached to a string in a horizontal circle. If the string snaps
the ball will travel towards the centre of the circle and fall down
it will continue to travel along a tangent to the circle at the point the ball was at the time of snapping and finally fall down
it will fall down at the same place where the string breaks
None of these
The distance between two bodies is halved. Now the force of attraction between them will be
half
one fourth
four times
two times
The unit of heat energy is
watt
degree
joule
erg
A spherical mirror is
a reflecting elliptical portion
a reflecting spherical surface
a parabolic reflecting surface
a flat reflecting surface
The brightest star visible to the naked eye is
Sirius
Vega
Rigel
Proxima Centauri
Who discovered that the Cree Call acceleration Is the same for any object at a given place?
Newton
Pascal
Archimedes
Galileo
The principle on which a Jet engine works is
conservation of mass
Newtonian law of action and reaction
conservation of angular momentum
None of the above
Metals are good conductors of heat because
they contain free electrons
their atoms are relatively far apart
their atoms collide frequently
they have reflecting surfaces
The Indian Satellite System used for domestic communications, television and meteorology is known as
INSAT
Bhaskara
Aryabhatta
All the above
Mica is used in an electric iron because it is a
good conductor of heat
good conductor of electricity
bad conductor of electricity
Both (a) and (b) above
Diamond shines because of its
purity
hardness
high density
high refractive index and low critical angle
The presence of impurities
lowers the melting point of ice
raises the melting point of ice
has no effect on the melting point of ice
may lower or raise the melting point depending upon the type of impurities
Choose the scalar quantity from the following physical quantities
force
velocity
acceleration
speed
The device used to record the sound is
a microphone
a headphone
a phonograph
an amplifier
We cannot see and without the aid of a telescope
Neptune and Pluto
Jupiter and Saturn
Venus and Mars
Venus and Saturn
Out of the following which element has the longest half-life period?
Radium
Radon
Uranium-238
Plutonium
The solar wind is composed of
outward stream of protons and electrons on the surface of the sun during solar flares and sun-spot activity
plasma
ionized gas
All of these
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
The ballistic missile, Agni 11, tested by India has a maximum range of
1000 km
1500 km
2000 km
500 km
A ship sailing from a river to the sea
sinks less in the sea
sinks more in the sea
neither sinks more nor less in the sea
sinking more or less depends on sea
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
The device for tracking and locating the position of a moving object in space is called
Space ship
Lunar module
Radar
Rocket
The radiator in a car serves to
cool the engine
heat up the engine
start the car
moderate the speed
A simple mercury barometer is found in a slightly slanting position. The atmospheric pressure
is found by measuring the slanting height of the mercury column
is given by the vertical height
cannot be measured with it
u) can be measured by both the methods described above
Skating on ice is possible because
the surface of ice is smooth
ice is cold
the pressure on the ice due to skate melts the ice by lowering its melting point forming a thin film of water
the pressure on the ice due to skate raises its melting point