The number of electrons in the outer orbits of a nucleus gives
the mass number
atomic number
atomic weight
absolute number
Correct Answer :
B. atomic number
Related Questions
The velocity required to place a vehicle in orbit round the moon is _________ that required to place it in orbit round the earth.
less than
greater than
equal to
greater than or equal to
Primary colours are
colours of the rainbow
colours in the spectrum of white light
colours which cannot be produced by mixing other colours
colours found in nature
The best estimates of the age of the earth comes from the studies of
angle of inclination of the earth
changes in radio-active minerals in it
period taken by Sun's light to reach the earth
artificial satellites revolving round the earth
Nichrome is used in electric heaters and irons because
it resists oxidation when red hot
its melting point is high
it has got 60 times the resistance of copper
All the above
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
In a refrigerator cooling is produced by
the ice that deposits on the freezer
the evaporation of a volatile liquid
None of the above
Both (a) and (b)
In the fuse of an electrical installation blows out
replace the fuse by a thin wire
replace the fuse by a thick copper wire
replace the fuse by a fuse wire of proper rating
replace the fuse by nichrome wire
The radius of curvature of a spherical mirror is
equal to half its focal length
equal to its focal length
twice its focal length
not related to its focal length
The mass number and the atomic number of an element are X and Y respectively. The number oC neutrons in the atom of that element is
X
Y
X + Y
X Y
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
The maximum displacement of the particle in a mechanical wave motion is known as
amplitude
vibration
frequency
phase
Which physical quantity is measured in watts
power
kinetic energy
momentum
impulse
Electromagnets are used in
the telephone ear piece
the telegraph
the electric bell
All the above
Choose the scalar quantity from the following physical quantities
force
velocity
acceleration
speed
The method used to separate aluminium from a alumina is
electroplating
electrotyping
electrolysis
distillation
The focal length or lens or the eye is under the control or the
iris
pupil
ciliary body
cornea
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
A permanent magnet may be demagnetised by
placing it inside a solenoid through which an alternating current is flowing
heating the magnet to redness and then allowing it to cool
dropping it several times or hammering it while lying east-west
All the above
A bar magnet tied in the middle with a thread is suspended at the South Pole of the earth. The magnet will be in
a horizontal position
a nearly vertical position with its South Pole downwards
a nearly vertical position with its North Pole downwards
a slanting position
The motion .of the pendulum of a wall clock is an example of
linear motion
vibratory motion
rotational motion
None of the above
The spectrum of white light can be studied by
a microscope
a telescope
a stereoscope
a spectroscope
When are temperature resistance
increases
decreases
remains the same
first increases then decreases
A lightning conductor installed in a building
does not allow the lightning to fall on the building at all
drives away the charged clouds
forces the lightning to fall on other buildings near that building
conducts the electric charges to the ground when lightning strikes the building
Enriched uranium means
Uranium that is very pure
Uranium in which the concentration of the isotope U-238 is more than in the naturally occuring uranium
Uranium in which the concentration of the isotope U-235 is more than in the naturally occuring uranium
None of the above
A workman was working on a rail track. A young boy at a distance holds his ear close to the railway track. The boy was able to hear the sound of each blow or the workman twice. It is because
speed of sound is greater in steel than in air
speed of sound is greater in air than in steel
part of sound waves is reflected between rail tracks
the boy's ears are at a different distance from the source
When are temperature resistance
increases
decreases
remains the same
first increases then decreases
Out of the following which is an insulator?
Silver
Copper
Nichrome
Dry wood
The unit of heat energy is
watt
degree
joule
erg
Raindrops assume a spherical shape because or
adhesion
surface tension
gravitational force
atmospheric pressure from all sides
The instrument used to determine the RD (Relative Density) of a liquid by the principle of floatation is
Hygrometer
Hypsometer
Hydrometer
Densimeter