A tube light works on the principle of
chemical, heating and magnetic effects of electricity
discharge of electricity through gases
the action of ultraviolet radiation on certain fluorescent materials
Both (b) and (c) above
Correct Answer :
D. Both (b) and (c) above
Related Questions
For detecting and, testing of small electric charges we use
an electrophorus
an electroscope
an electromagnet
an ammeter
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
Solids have definite shapes. This is because
the forces of cohesion of the molecules within are very much less in them
the forces of cohesion are very large
the forces of adhesion are large
the forces of adhesion are less
Which force is used when milk is churned to separate cream?
cohesive
centrifugal
frictional
gravitational
'Acoustics' is a branch or study dealing with
historical sites
architecture
sound
trigonometry
Which mirror is used as a rear view mirror in Vehicles?
Parabolic
Convex
Concave
Plain
Why is it cool near an open pond on a hot summer day?
Evaporation at the surface causes cooling
The heat obsorbed at the surface is passed on to the bottom
Because of impurity in the water
Because of convection currents set up inside water
To concentrate light on the defective teeth, the dentists use
convex mirrors
concave mirrors
convex lens
concave lens
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
At what temperature do the Fahrenheit and Celsius scales give the same reading?
212°
32°
-40°
0°
If the speed of the rotation of the earth increases the weight of a body
will increase
will decrease
will have no change
will either increase or decrease
The Space Application Centre for training in Satellite Communication Technology is located at
Bangalore
Mumbai
Ahmedabad
New Delhi
The speed of light is minimum while passing through
air
glass
vacuum
water
For an electron orbiting in a hydrogen atom, the necessary centripetal force keeping it in orbit is provided by
the electrical attraction between the negatively charged electron and the positively charged porton
the high speed of the electron
the low speed of the electron
gravity
The Space Application Centre for training in Satellite Communication Technology is located at
Bangalore
Mumbai
Ahmedabad
New Delhi
Gamma radiations are used for
sterilising food stuff
controlling pests
cancer therapy
All of these
The mixing up of two gases as a result of random motion of molecules is called
diffusion
effusion
vaporisation
sublimation
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
Besides protons, the nucleus of an atom contains
electrons
neutrons
neutrons and electrons
electrons, neutrons and other particles
A device used to measure heights above sea level is known as
altimeter
anemometer
dilatometer
potentiometer
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
The colour of the light which travels through glass with minimum speed is
red
violet
green
yellow
When water is cooled from 4�C to 2�C its density
increases
decreases
remains the same
first increases then decreases
If a body weight 12N on the surface of the earth, how much will it weigh on the surface of the moon where acceleration due to gravity is only one-sixth of that on earth's surface?
12N
2N
10N
6N
Alternating Current (AC) is more advantageous than direct current because
it can be transmitted easily and efficiently
Alternating Current (AC) loses the least amount of energy when transmitted at high voltages
Alternating Current (AC) voltage can be easily increased or decreased
all the above
Pieces of camphor placed on water move about rapidly. This is because of
diffusion
viscosity
surface tension
capillarity
The stars that shine brightly then dimly and then brightly are known as
meteors
binaries
variable stars
bright stars
Light from the sun reaches the earth in
2 minutes
4 minutes
12 minutes
8 minutes
The shadow below a tree has bright spots in it because
light comes through circular gaps between the leaves
the leaves are circular
the rays bend to form circular spots
the gaps between the leaves act as pin holes
Compared to the atomic bomb, the destructive power of a hydrogen bomb is
greater
less
equal
can't be determined