A radio set that uses valves does not start operating immediately when it is switched on whereas a set containing only tranaistors operates immediately. The reason for this is that
the valve filaments have low resistance
valve-radio sets work at a higher voltage
transistor set has a low resistance
filaments of the valves cake time to beat up and function
Correct Answer :
D. filaments of the valves cake time to beat up and function
Related Questions
The instrument used to measure the strength of electric current at a point is
Ammeter
Altimeter
Adrinometer
Anemometer
In the visible spectrum which colour has the shortest wavelength?
Red
Blue
Yellow
Violet
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
Electromagnets are used in
the telephone ear piece
the telegraph
the electric bell
All the above
The asteroids belt lies between the orbits of
Earth and Mars
Venus and Earth
Mars and Jupiter
Moon and Mars
Mercury is used in a barometer because
its density being very high 13.6 g/cm3 the height of mercury column is conveniently small
at the ordinary temperature its vapour pressure is small
it is opaque and does not wet glass
All the above
A man Jumping out of a moving train is thrown
forward
backward
sideways
None of the above
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
The study of astronomy include a
astrology
astrophysics
astrometry
Both (b) and (c) above
The number of galaxies that are visible without telescope on clear dark nights and away from bright lights is
one
two
three
infinite
Which of the following apparatus is used in the electrolysis of water?
Voltmeter
Voltameter
Ammeter
Potentiometer
The device used to record the sound is
a microphone
a headphone
a phonograph
an amplifier
When a bottle of perfume la 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 planet that has got a well-developed set of rings is
Venus
Saturn
Mercury
Earth
A timer in a race is at the finish line. He should start his stop watch
as soon as he hears the report of the gun
the moment he sees the flash
either (a) or (b) since that makes no difference
None of the above
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
Hot water is poured simultaneously in four metallic tumblers painted outside with different paints. After some time the water will be found to have cooled most in the tumbler painted.
rough white
rough black
shining white
shining black
Tea pots are highly polished
so that they may reflect thermal radiation from outside and minimise such radiation from them
so that they may absorb all radiation from outside
to make them attractive to look at
because they take high polish
'Acoustics' is a branch or study dealing with
historical sites
architecture
sound
trigonometry
An astronomical unit of distance is
a kilometre
light year
the average distance from the earth to the sun
None of the above
The minimum velocity required by a satellite to escape earth's gravitational pull is
18 km/s
11.2 km /s
21 km/s
35 km/s
Among the following the most suitable material for the core of an electro-magnet is
steel
wood
soft iron
copper
Out of the following which element has the longest half-life period?
Radium
Radon
Uranium-238
Plutonium
Electromagnets are used in
the telephone ear piece
the telegraph
the electric bell
All the above
The planet that moves fastest around the sun is
Mars
Venus
Earth
Mercury
Acoustics is a property or
Physics
Chemistry
Biology
Economic
When a bullet is fired from a gun
the gun moves forward
the gun jumps up
the gun does not move
the gun recoils with the same momentum as the bullet
For accurate scientific work, temperatures are often measured by
mercury thermometers
alcohol thermometers
platinum resistance thermometers
thermoelectric thermometers
You want a supply of a small but constant current. Which of the following cells will you prefer?
Daniell cell
Leclanche cell
Dry cell
All the above
A man weighing 50 kg floats on water in a lake. His apparent weight is
50 kg
45 kg
zero
150 kg