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
Correct Answer :
D. it is ready to produce controlled energy
Related Questions
The phenomenon of radioactivity was discovered by
Rutherford
Bohr
Henri Bacquerel
Marie Curie
To concentrate light on the defective teeth, the dentists use
convex mirrors
concave mirrors
convex lens
concave lens
A transformer
converts direct current into alternating current
converts alternating current into direct current
steps up or steps down a given alternating current voltage
supplies current with zero resistance
Cosmic rays are
powerful X-rays falling on the earth from space
ultraviolet rays from the sun
gamma rays from radioactive minerals
very energetic radiation falling upon the earth from outer space consisting chiefly of charged particles
Which of the following is not electromagnetic waves?
heat waves
sound waves
radio waves
light waves
Which of the following has the highest refractive index?
Crown glass
Water
Flint glass
Diamond
When are temperature resistance
increases
decreases
remains the same
first increases then decreases
The end product in the uranium disintegration series is
lead
zinc
carbon
tin
An electric charge is measured in
coulomb
ampere
volt
watt
The hygrometer is an apparatus used for finding the
temperature of air
intensity of light
density of a liquid
relative humidity of the atmosphere
Cyclotron is an apparatus used
as an accelerator for imparting energies to charged particles of atomic magnitudes
to reduce the charge on a particle
to produce intense magnetic field
to produce intense electrical field
Which metal is used in storage batteries?
Copper
Lead
Tin
Iron
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
Air escaping rapidly from a narrow orifice in an inflated tyre feels cool because
the speed with which it escapes cools it down
of the higher temperature of the surroundings
of sudden expansion causing loss of internal energy
there is no real fall in temperature
The plants in a greenhouse are enclosed in a glass enclosure because
glass allows the heat radiations of shorter wavelengths from the sun to pass through
the plants absorb them - these shorter wavelengths - and reradiate them in the form of longer wavelengths
the longer wavelengths cannot penetrate through the glass walls
All the above
The tiniest of the stars belong to the group known as
Giant stars
White Dwarf stars
Neutron stars
Super-giant stars
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
A temperature below absolute zero for an ideal gas
cannot be attained experimentally
can be attained
is impossible
Does not exist at all
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 attraction between similar molecules is called
inertia
adhesion
cohesion
friction
The evaporation rate depends on
the nature of the liquid
area of the exposed surface of the liquid
temperature of air and of the liquid
All the above
X-rays were discovered by
Wilhelm Roentgen
WO Coolidge
Henry Cavendish
William Watson
The base of an electric iron is brightly polished mainly
to make it smooth and frictionless
to make it rust - proof
to reduce heat loss by radiation
to make it more durable
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
Red Light is used as a dancer signal because
it is pleasing to the eye
it has a traditional colour
it is easily distinguishable
it is most sensitive to the human eye
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
At what temperature do the Fahrenheit and Celsius scales give the same reading?
212°
32°
-40°
0°
Which of the following revolves round the nucleus in an atom?
protons
electrons
neutrons
positrons
The instrument used to determine the RD (Relative Density) of a liquid by the principle of floatation is
Hygrometer
Hypsometer
Hydrometer
Densimeter
The planet with the reddish tinge is
Jupiter
Mars
Mercury
Saturn