Out of the following which element has the longest half-life period?
Radium
Radon
Uranium-238
Plutonium
Correct Answer :
C. Uranium-238
Related Questions
The atmosphere gets heated up mainly by
direct sun's rays
radiation from earth's surface
radiogenic heat (resulting from radioactive decay)
cosmic rays coming from space
Dioptre is the unit of power of
convex mirrors
concave mirrors
concave lenses
lenses irrespective of types
When the disturbed electrons of an exited atom transfer back into lower energy levels they emit energy in the form of electromagnetic wave pulses called
neutrons
electrons
phonons
photons
The aneroid barometer uses
mercury
distilled water
alcohol
does not use any liquid
X-rays are used
in hospital in the treatment of malignant growth
to reveal hidden flaws in metal castings and welded joints
to detect alterations made in works of art
All the above
Thick brick walls are used in the construction or a cold storage because bricks
are good conductors of heat
are cheaper
are easily obtained
are bad conductors of heat
The distance between two bodies is halved. Now the force of attraction between them will be
half
one fourth
four times
two times
The nuclear model of atom was first visualised by
Rutherford
Neils Bohr
Albert Einstein
JJ Thompson
Water kept in an earthen pot is less cool on rainy days than in summer because during the rainy days
the pores in the pot are closed
rain water stops oozing out from the pores
the water that oozes out does not evaporate quickly because of the large percentage of moisture in the air
surface of the pot becomes damp
The ozone layer absorbs
Cosmic rays
Infrared rays
All radiations of light
Ultra violet rays coming from the sun
A piece of cork is 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 focal length or lens or the eye is under the control or the
iris
pupil
ciliary body
cornea
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
Astigmatism, a structural defect of the eye, is due to
the eye lens being thin
the eye lens being thick
lack of symmetry in the curvature of the eye preventing rays of light from being brought to a common focus
the pupil being very small
Which of the following is not electromagnetic waves?
heat waves
sound waves
radio waves
light waves
A car parked in the sun with its windows closed gets terribly hot inside. This is due to
the heat emitted by the engine
the greenhouse effect
the good conducting power of the metal body
the double layered wind shield
The enormous energy released in nuclear and thermonuclear reactions is due to conversion of
chemical energy into heat energy
mechanical energy into heat energy
protons into neutrons
mass into energy according to Einstein's equation
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
When one enters a dark room after being in bright light one is not able to see anything clearly for a while because
the retina of the eye moves forward
the retina of the eye moves backward
c).the iris is unable to dilate the pupil immediately to be able to see things
the eye has no power of accommodation
Which of the following wires of same dimensions offers least resistance to the ,flow of current?
copper
aluminium
silver
nichrome
The escape velocity of a satellite projected from the surface of the earth is independent of
the mass of earth
the mass of the satellite
the radius of the earth
gravitation of the earth
Besides protons, the nucleus of an atom contains
electrons
neutrons
neutrons and electrons
electrons, neutrons and other particles
Of the following types of electromagnetic radiation which has the longest wavelength?
ultraviolet rays
gamma rays
radio waves
infrared waves
A light year means
a unit of time
a unit of length
a year of no consequence
illumination throughout the year
Some persons are not able to see distant objects clearly because the image of the object is focused in front of the retina. This defect is known as
short sight
long sight
astigmatism
presbyopia
The Indian Space Research Organisation (ISRO) is located at
Thumba
Bangalore
Ahmedabad
New Delhi
The loudness of a sound is determined by
Frequency
Amplitude
Speed
Wavelength
The electroplating of a metallic article
protects the article from atmospheric corrosion
gives it a more attractive appearance
Both (a) and (b) above
None of the above
The attraction between similar molecules is called
inertia
adhesion
cohesion
friction
For detecting and, testing of small electric charges we use
an electrophorus
an electroscope
an electromagnet
an ammeter