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
In which of the following will a piece of iron weigh most?
in air
in an atmosphere of oxygen
in an atmosphere of CO2
in vacuum
The phenomenon of radioactivity was discovered by
Rutherford
Bohr
Henri Bacquerel
Marie Curie
A hydrogen bomb is based on
nuclear fusion
nuclear fission
Both (a) and (b) above
Neither (a) nor (b)
During thunder storm you are travelling in a car. To protect yourself from the lightning you will have to
remain in the car
get out of the car and lie flat in the ground
abandon the car and take shelter under a nearby tree
touch the nearest electric pole
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
Compared to the atomic bomb, the destructive power of a hydrogen bomb is
greater
less
equal
can't be determined
The planet that spins Caster than any other planet is
Saturn
Jupiter
Earth
Mercury
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
Which metal is used in storage batteries?
Copper
Lead
Tin
Iron
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
Which of the following is known as freon?
Liquid ammonia
Carbon tetrafluoride
Dichloro-difluoro-methane
Sulphur dioxide
When an electric bulb breaks, there is an explosive sound. That is due to
the chemical reaction between the gases inside the bulb
the compressed gases inside rushing out suddenly
the air outside rushing in to fill the vacuum inside the bulb
None of the above
When the earth reaches its perihelion
it is nearest to the moon
it is nearest to the sun
it is nearest to Pluto
it is farthest from the sun
Electromagnets are used in
the telephone ear piece
the telegraph
the electric bell
All the above
A simple mercury barometer is found in a slightly slanting position. The atmospheric pressure
is found by measuring the slanting height of the mercury column
is given by the vertical height
cannot be measured with it
can be measured by both the methods described above
An electric kettle used for boiling hard water has a white scale deposited on its heating element. This consists or
sugar
sodium carbonate
common salt
carbonates of calcium and magnesium
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 presence of impurities
lowers the melting point of ice
raises the melting point of ice
has no effect on the melting point of ice
may lower or raise the melting point depending upon the type of impurities
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
'Acoustics' is a branch or study dealing with
historical sites
architecture
sound
trigonometry
The nuclear model of atom was first visualised by
Rutherford
Neils Bohr
Albert Einstein
JJ Thompson
The transistor was invented by
Marconi
Baird
John Bardeen, Walter H. Brattain and William Shockley
Edison
Drinks kept in a vacuum flask remain hot or cold as the case may be for a long time because
both walls are silvered on the vacuum side
there is vacuum between the double walls
the cork is a poor conductor of heat
of all the above
The earth satellite Aryabhatta was put in orbit by India on
October 20, 1978
November 14, 1978
January 26, 1979
April 19, 1975
Nuclear fission process means
absorption of a neutron by a nucleus
breakup of the nucleus of a heavy atom into two nearly equal halves emitting two or three neutrons and releasing large amounts of nuclear energy in the process
the scattering of neutrons
formation of heavier nucleus
The principle of equivalence of mass and energy was established by
Dalton
Rutherford
Einstein
Planck
A boat loaded with rocks floats in the middle of a swimming pool. A man in the boat throws the rocks overboard. The level of water in the pool will
increase
decrease
remain the same
first decrease and then increase
Mercury is used in thermometers because
it has high thermal conductivity
it has uniform expansivity
it has high boiling point and low freezing point
of all the above
The ozone layer absorbs
Cosmic rays
Infrared rays
All radiations of light
Ultra violet rays coming from the sun
Metals are good conductors of heat because
they contain free electrons
their atoms are relatively far apart
their atoms collide frequently
they have reflecting surfaces