A balloon ruled with hydrogen will
continue going upwards uninterrupted
reach a particular height and remain floating
burst after reaching some height
reach a particular height and start coming down
Correct Answer :
B. reach a particular height and remain floating
Related Questions
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
If a man wants to hear clearly the echo of a sound produced by him from a hill, the hill should be away from him by a minimum distance of
330 m
33 m
16.5 m
165 m
The nuclear model of atom was first visualised by
Rutherford
Neils Bohr
Albert Einstein
JJ Thompson
When the velocity of a body is halved
its momentum is halved
its kinetic energy is halved
its acceleration is halved
its potential energy is halved
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
In the fuse of an electrical installation blows out
replace the fuse by a thin wire
replace the fuse by a thick copper wire
replace the fuse by a fuse wire of proper rating
replace the fuse by nichrome wire
The Milky Way is
the path of a star which is nearest to the earth
a galaxy which includes the sun
a star that is nearest to the earth
None of these
The tiniest of the stars belong to the group known as
Giant stars
White Dwarf stars
Neutron stars
Super-giant stars
When water is cooled from 4�C to 2�C its density
increases
decreases
remains the same
first increases then decreases
X-rays are used
in hospital in the treatment of malignant growth
to reveal hidden flaws in metal castings and welded joints
to detect alterations made in works of art
All the above
Moon has no atmosphere because
it has no population
it is quite far off
its surface is full of rocks
its gravity is not sufficient for any atmosphere to hold on to it
A star contains
about 75% of hydrogen
22% helium
traces of most other elements including oxygen, neon, carbon and nitrogen
All the above
The asteroids belt lies between the orbits of
Earth and Mars
Venus and Earth
Mars and Jupiter
Moon and Mars
Meteors
look like falling stars
are really pieces of rock or metal
burn up as they shoot through the air
All the above
A bolometer is used to measure
the quantity of heat energy in a body
thermal radiations quantitatively
high temperature
the intensity of sound
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
Water has maximum density at
0° C
-15° C
4° C
15° C
An electric charge is measured in
coulomb
ampere
volt
watt
The period of oscillation of a simple pendulum depends upon
the mass of its bob
the material of the bob
the amplitude of vibration
acceleration due to the gravity at the site of experiment
When we tighten the string of a sitar or tanpura its pitch
remains the same
increases
decreases
None of the above
The colour or an opaque object is due to the colour it
absorbs
refracts
reflects
scatters
The planet that has got a well-developed set of rings is
Venus
Saturn
Mercury
Earth
During thunder storm you are travelling in a car. To protect yourself from the lightning you will have to
remain in the car
get out of the car and lie flat in the ground
abandon the car and take shelter under a nearby tree
touch the nearest electric pole
A lightning conductor installed in a building
does not allow the lightning to fall on the building at all
drives away the charged clouds
forces the lightning to fall on other buildings near that building
conducts the electric charges to the ground when lightning strikes the building
In the case of bodies falling under gravity which of the following remains constant at a given place?
kinetic energy
potential energy
acceleration
All the above
Mercury does not stick to glass because
cohesive forces between the mercury molecules are greater than adhesive forces between mercury and glass molecules
the adhesive forces between mercury and glass molecules are greater than the cohesive forces
both the cohesive and adhesive forces are equal
None of the above
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
When light passes from air to glass, its velocity in glass
increases
decreases
remains unchanged
first decreases then increases
How is it that Pluto is not always the farthest planet of the solar system?
Each planet becomes the farthest planet in its turn. Now it is the turn of Piuto
The Sun is now in the zodiac in which it is nearest to outer planets
The eccentricity of Piuto's orbit being substantial, this orbit cuts the orbit of Neptune
Piuto belongs to other solar system
The device for tracking and locating the position of a moving object in space is called
Space ship
Lunar module
Radar
Rocket