Velocity of sound in high altitudes is low because at such a height
the temperature is low
there is no air
the pressure is low
All the above
Correct Answer :
A. the temperature is low
Related Questions
Railway tracks are banked on curves so that
the necessary centrifugal force may be obtained from the horizontal component of the weight of the train
the frictional force between the track and the wheels is avoided
the necessary centripetal force may be derived from the horizontal component of the weight of the train
None of these
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
When a body is partly or wholly immersed in a liquid the apparent loss of weight is equal to the weight of the liquid displaced by the submerged portion. This is known as
Pascal's law
Bernoulli's law
Archimedes' law
Boyle's law
The unit of power in SI is
Joule
Newton
Joule/Sec
Erg/Sec
The temperature of a large bucket-full of hot water (a few degrees below boiling point) is lower than a beaker full of boiling water. But
the hot water contains a much larger quantity of internal energy than the boiling water
the boiling water contains more quantity of internal energy than the warm water
both of them have got the same amount of internal energy.
nothing can be said definitely with the data given
Gamma radiations are used for
sterilising food stuff
controlling pests
cancer therapy
All of these
What la the minimum velocity required for a rocket to overcome earth's gravity and travel into space?
18 km/sec
11.2 km/ sec
21 km/ sec
35 km/ sec
The hydraulic jack to lift heavy vehicles in automobile service stations is one of the applications of
Pascal's law
Principle of Archimedes
Boyle's law
Hooke's law
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
Red Light is used as a dancer signal because
it is pleasing to the eye
it has a traditional colour
it is easily distinguishable
it is most sensitive to the human eye
The device for tracking and locating the position of a moving object in space is called
Space ship
Lunar module
Radar
Rocket
When one enters a dark room after being in bright light one is not able to see anything clearly for a while because
the retina of the eye moves forward
the retina of the eye moves backward
c).the iris is unable to dilate the pupil immediately to be able to see things
the eye has no power of accommodation
The frequency of an ultrasonic wave is
the same as that of an audible sound
above the audible range
below the audible range
None of the above
Chronometer la an instrument to measure
heat
electric potential
time
distance between two points
The ringing of an electric bell in an enclosed evacuated glass bell jar is not heard outside because
the ringing is not loud enough
the glass of the bell jar absorbs the sound waves
the bell jar is too small
there is no air or -any other gas in the bell jar
The planet that moves fastest around the sun is
Mars
Venus
Earth
Mercury
The number of galaxies that are visible without telescope on clear dark nights and away from bright lights is
one
two
three
infinite
The largest reserve of radioactive element which can be used in a nuclear reactor has been found in India, The name of the element is
Thorium
Uranium
Plutonium
Radium
Drinks kept in a vacuum flask remain hot or cold as the case may be for a long time because
both walls are silvered on the vacuum side
there is vacuum between the double walls
the cork is a poor conductor of heat
of all the above
The focal length or lens or the eye is under the control or the
iris
pupil
ciliary body
cornea
In a concert hall reverberation is controlled by
reduction of seating capacity in the hall
increase of sound intensity in the hall
lining the walls, with leather panels put on over a layer of sound absorbent glass fibre
by opening the doors and windows of concert hall
Which mirror is used as a rear view mirror in Vehicles?
Parabolic
Convex
Concave
Plain
The electrical domestic tube light gives white fiourescent light because of
collision between molecules of filled gas under electric current
heavy current
vacuum inside the tube
falling of ultra violet rays on the white inner coating of the tube
The body of an electrical appliance is earthed in order that
electricity may not leak
there may be smooth flow of electricity
a short circuit may be prevented
current may pass to the earth in case of a short circuit without doing any harm to the person
An astronomical unit of distance is
a kilometre
light year
the average distance from the earth to the sun
None of 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
A projectile is fired at an angle with the horizontal with a small velocity. Its horizontal range will be maximum when the angle with the horizontal is
0°
30°
45°
60°
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
If an object is placed between two parallel plane mirrors, the number of images formed will be
1
infinite
0
4
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