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
Correct Answer :
D. falling of ultra violet rays on the white inner coating of the tube
Related Questions
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
When temperature decreases, resistance of metals to flow of electricity
increases
decreases
neither increases nor decreases
first increases then decreases
The red colour of the setting sun is due to
the least scattered red colour reaching the eye
the dispersion of sun light occurred in air molecule in atmosphere
the diffraction of sunrays in atmospheric layers
interference of all the rays coming from the sun
When a bottle of perfume is opened in one corner of a room the smell spreads soon throughout the room. This is an example of
surface tension
capillarity
viscosity
diffusion
The audible range of a normal human ear is frequencies ranging from
10000 to 20000 Hz
50 to 15000 Hz
20 to 20000 Hz
15 to 50000 Hz
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
In the visible spectrum which colour has the shortest wavelength?
Red
Blue
Yellow
Violet
When a steel ball is placed on the surface of mercury, it does not sink because
of the surface tension of mercury
mercury is a semi-solid
of the high viscosity of mercury
the density of mercury is greater than that of steel
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
Some persons are not able to see distant objects clearly because the image of the object is focused in front of the retina. This defect is known as
short sight
long sight
astigmatism
presbyopia
In very cold countries alcohol is used as a thermometric liquid because
alcohol is a poor conductor of heat
alcohol can be coloured for its level to be seen easily
its freezing point is very low
it will not stick to the glass tube
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
Separating particles from a suspension is effected by
centrifugal force
frictional force
gravitational force
distillation
The instrument used to measure atmospheric pressure is
Pyrometer
Eudiometer
Barometer
Hydrometer
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 is the densest planet of the solar system?
Sun
Jupiter
Mercury
Earth
A photon is
a quantum of electromagnetic radiation
light source used in photography
a photo film
sun-light
A ship sailing from a river to the sea
sinks less in the sea
sinks more in the sea
neither sinks more nor less in the sea
sinking more or less depends on sea
The device that is used to measure the electromotive force of a cell is
an ammeter
a rheostat
a voltmeter
a voltameter
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
Before the invention of geostationary satellites, television stations could not transmit their programmes to far off places because
these signals are electromagnetic in nature
these are not electromagnetic in nature
their wavelength is very large
they are not reflected by the ionosphere but pass through it
We see the sun before it actually rises on the horizon. This is due to
refraction
reflection
total internal reflection
parallax
In a hydraulic pressure
force on each square centimetre of the small piston is less than the force on each square centimetre of the large piston
the distance the small piston moves is equal to the distance the large piston moves
applied pressure is equally transmitted throughout the liquid in all directions
force acting on small piston is equal to the force acting on large piston
The inability of a body to change its state of rest or uniform motion along a straight line is called its
momentum
velocity
acceleration
inertia
Sun spots are
the mountains found on the surface of the Sun
the dark patches on the sun having less temperature than the normal sun's surface
ionized gas found near the solar surface
the magnetic storms on the surface of the Sun
When are temperature resistance
increases
decreases
remains the same
first increases then decreases
The rocket engine is motivated by jet propulsion which uses the famous
Kepler's Laws
Newtonian Third Law of Motion
Bernoulli's Principle
Law of Relativity
The aneroid barometer uses
mercury
distilled water
alcohol
does not use any liquid
The heat produced in a conductor due to the passage of a current through it is proportional to
the square of the current
the resistance of the conductor
the time for which the current flows
All the above
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