In the electrical circuit of a house the fuse acts as
a thermopile
a load
a step down device
a safety device
Correct Answer :
D. a safety device
Related Questions
Lightning conductors are made of
iron
chromium
copper
steel
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
A temperature below absolute zero for an ideal gas
cannot be attained experimentally
can be attained
is impossible
Does not exist at all
The line on earth's surface passing through the places having zero dip is called the magnetic equator. This passes through
Thumba
Delhi
Mumbai
Sriharikota
Which force is used when milk is churned to separate cream?
cohesive
centrifugal
frictional
gravitational
The coil of an electric heater is made of
Platinum
Tungsten
Nichrome
Copper
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
The loudness of a sound is determined by
Frequency
Amplitude
Speed
Wavelength
The aneroid barometer uses
mercury
distilled water
alcohol
does not use any liquid
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
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
A person does not sink in the Dead Sea because
the sea contains a large amount of other salts besides sodium chloride
the density of the person is less than the density of the Dead Sea water
of the surface tension due to salt water in the Dead Sea
of difference in mass
A nuclear reactor is said to have become 'critical' when
it stops due to malfunctioning
it starts emitting dangerous radioactive radiations
it is shut down to avoid explosion
it is ready to produce controlled energy
The instrument used to determine the RD (Relative Density) of a liquid by the principle of floatation is
Hygrometer
Hypsometer
Hydrometer
Densimeter
The transistor was invented by
Marconi
Baird
John Bardeen, Walter H. Brattain and William Shockley
Edison
An electric charge is measured in
coulomb
ampere
volt
watt
A proton is
a quantum of light energy
a quantum of matter
a positively charged atomic particle
another name for positron
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
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 light travels from one medium to another there is a change in its
velocity
wavelength
frequency
Both (a) and (b) above
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 solar wind is composed of
outward stream of protons and electrons on the surface of the sun during solar flares and sun-spot activity
plasma
ionized gas
All of these
When two similar sources vibrate with slightly different frequencies, a regular rise and fall occurs in the loudness of tone. This phenomenon Is known as
doppler effect
beats
resonance
echo
A spherical mirror is
a reflecting elliptical portion
a reflecting spherical surface
a parabolic reflecting surface
a flat reflecting surface
Why is nuclear fusion also known as thermonuclear reaction?
Fusion converts nuclear energy into heat
Fusion demands conditions of extremely high temperature to produce it
Fusion produces large amount of heat
Fusion reactions takes place in the sun
The barometer was invented by
Michael Faraday
Torricelli
Thomas Alva Edison
Benjamin Franklin
A piece of cork la embedded inside an ice block which floats in water. What will happen to the level of water when all ice melts?
It will go down
It will come up
It will remain at the same level
First it will go down and it will come up
The phenomenon of spontaneous disintegration of certain heavy nuclei is termed
radioactivity
fission
fusion
implosion
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 attraction of unlike molecules at the common surface is known as
adhesion
cohesion
surface tension
capillarity