Photoelectric cell is a device which converts
light energy into electrical energy
electrical energy into light energy
magnetic energy into electrical energy
electrical energy into mechanical energy
Correct Answer :
A. light energy into electrical energy
Related Questions
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
Besides protons, the nucleus of an atom contains
electrons
neutrons
neutrons and electrons
electrons, neutrons and other particles
Changing of one element into another element is known as
transmutation
fission
fusion
radioactivity
The heat generated in a conductor carrying current is proportional to
the resistance
the square of the current flowing through it
the time the current flows
All the above
Water kept in an earthen pot is less cool on rainy days than in summer because during the rainy days
the pores in the pot are closed
rain water stops oozing out from the pores
the water that oozes out does not evaporate quickly because of the large percentage of moisture in the air
surface of the pot becomes damp
The number of galaxies that are visible without telescope on clear dark nights and away from bright lights is
one
two
three
infinite
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
A spherical mirror is
a reflecting elliptical portion
a reflecting spherical surface
a parabolic reflecting surface
a flat reflecting surface
A car parked in the sun with its windows closed gets terribly hot inside. This is due to
the heat emitted by the engine
the greenhouse effect
the good conducting power of the metal body
the double layered wind shield
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
The difference between planets and stars is
planets do not have light of their own whereas stars shine by their own light
planets do not twinkle like stars
planets are much smaller than stars
All the above
The SI unit of electric current is
the ampere
the volt
the ohm
the coulomb
The mode of travel of heat energy from the sun across the empty space beyond the earth's atmosphere is known as
conduction
convection
radiation
absorption
The strength of an electromagnet can be increased by
increasing the length of the coiled wire
increasing current supply
increasing the size of the iron core
All the above
The attraction of unlike molecules at the common surface is known as
adhesion
cohesion
surface tension
capillarity
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
Radio waves sent out by radio stations are reflected by
troposphere
stratosphere
mesosphere
ionosphere
An ammeter has
a high resistance
a very low resistance
no resistance at all
resistance of 400 ? w
The principle of equivalence of mass and energy was established by
Dalton
Rutherford
Einstein
Planck
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
Holography is the technique of
taking photos of various objects
recording and reproducing three dimensional images
tracing out planets and stars in the sky
transmitting light waves
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
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
The cover of a solar cooker is made of glass because
it absorbs sun's rays
it reflects sun's rays
it retains the heat inside by the greenhouse effect
it radiates heat better than metals
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
Enriched uranium means
Uranium that is very pure
Uranium in which the concentration of the isotope U-238 is more than in the naturally occuring uranium
Uranium in which the concentration of the isotope U-235 is more than in the naturally occuring uranium
None of the above
When a body is immersed in a fluid the force of buoyancy of the fluid on the body depends on
the immersed volume of the body
density of the liquid
acceleration due to the gravity at the place
All the above
While crossing a suspension bridge, the soldiers are ordered to break steps because
the marching in steps will involve a big strain on them
the resonant vibrations caused by their marching can damage the bridge increasing the amplitude to dangerous proportions
the marching may obstruct other traffic
rumblings of their marching may disturb the surroundings
At what temperature do the Fahrenheit and Kelvin scales give the same reading?
212°
32°
-40°
0°
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