The source of electric energy in an artificial satellite is
mininuclear reactor
a dynamo
a thermopile
solar cells
Correct Answer :
D. solar cells
Related Questions
In a dynamo
mechanical energy is converted to light energy
mechanical energy is converted to heat energy
mechanical energy is converted to electrical energy
electrical energy is converted to mechanical energy
One finds it more difficult to walk on ice than on a concrete road because
there is more friction on ice than on concrete surface
ice is soft and spongy while concrete is hard
the friction between ice and the feet is less than that between the concrete and the feet
None of them
A sensitive instrument susceptible to magnetic infiuence can be protected from external magnetic field by
enclosing it in a thick walled iron box
wrapping it with an insulator
by placing it inside a glass case
by surrounding it with fine copper gauze
Alpha particles are
electromagnetic radiations
helium nuclei
negatively charged particles
neutral particles
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
In the ramous equation of Einstein E = mc2 , 'c' denotes.
velocity of sound
velocity of light
a constant factor
wavelength of light
A hydraulic brake in an automobile uses
a fluid to transmit the braking force
the force applied by the driver
hydrogen gas and not any liquid
a vacuum brake
Galaxies emit
radio waves and X-rays
ultraviolet light waves
visible light waves
All the above
Photocells are used
in burglar alarms
in automotive devices for light switches
television cameras
All the above
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
Which of the following sets of elementary particles have nearly equal masses?
Neutron and Proton
Electron and Proton
Neutron and Electron
Proton, Neutron and Electron
What is 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
A cup of hot coffee is placed on a metal table in a room. By which of the following methods does it lose heat?
conduction and convection only
conduction and radiation only
convection and radiation only
conduction, convection and radiation
The completely dark portion of a shadow of an object is known as
umbra
penumbra
image
black portion of light
Changing of one element into another element is known as
transmutation
fission
fusion
radioactivity
To produce beats it is necessary to have two waves
travelling in opposite direction
of slightly different frequencies
of equal wavelength
of equal amplitude
If you want to open a door with les difficulty you push it
at the middle
at a point away from the hinge (near the rim)
near the hinge
None of 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
Radio waves sent out by radio stations are reflected by
troposphere
stratosphere
mesosphere
ionosphere
It is easier to climb down a staircase than climb up because in climbing down
work is done against gravity
the steepness of the staircase isn't felt
gravity assists
there is no friction between the legs and steps
Which is the densest planet of the solar system?
Sun
Jupiter
Mercury
Earth
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
The acoustical quality of a room depends on
the size and shape of the room
the ability of the ceiling, walls and floor to exclude unwanted sound
the use of furnishings made of sound absorbing materials
All the above
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
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
Cosmic rays are
powerful X-rays falling on the earth from space
ultraviolet rays from the sun
gamma rays from radioactive minerals
very energetic radiation falling upon the earth from outer space consisting chiefly of charged particles
A stone floor feels cold to the bare feet but a carpet on the same floor feels warm. This is because
the floor and carpet are at different temperatures
the stone conveys the heat away from the feet more rapidly than the carpet
the carpet is a better conductor of heat than the stone
the human body maintains a constant temperature
Expansion of a rod when heated
is proportional to its original length
is proportional to the increase of temperature
is inversely proportional to its original length
Both (a) and (b) above
A spherical mirror is
a reflecting elliptical portion
a reflecting spherical surface
a parabolic reflecting surface
a flat reflecting surface
A permanent magnet may be demagnetised by
placing it inside a solenoid through which an alternating current is flowing
heating the magnet to redness and then allowing it to cool
dropping it several times or hammering it while lying east-west
All the above