The Cact that the compass needle does not point true north was observed first by
Sir Isaac Newton
Columbus
Archimedes
Thomas Alva Edison
Correct Answer :
B. Columbus
Related Questions
A sensitive instrument susceptible to magnetic infiuence can be protected from external magnetic field by
enclosing it in a thick walled iron box
wrapping it with an insulator
by placing it inside a glass case
by surrounding it with fine copper gauze
Diamond shines because of its
purity
hardness
high density
high refractive index and low critical angle
A capillary tube is partially dipped vertically in a vessel containing water. Due to capillarity water rises in the tube. The height of water rise in the tube can be increased by
decreasing the radius of the capillary tube
increasing the radius of the capillary tube
increasing the height of water in the vessel
None of these
Like magnetic poles
attract each other
repel each other
neither attract nor repel
attract or repel depending upon the conditions
The motion .of the pendulum of a wall clock is an example of
linear motion
vibratory motion
rotational motion
None of the above
The world's first artificial satellite Sputnik I was launched by Russia in
1985
1957
1959
1960
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)
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
A man weighing 50 kg floats on water in a lake. His apparent weight is
50 kg
45 kg
zero
150 kg
In experiments on static electricity the standard method for obtaining small amounts of positive electricity is to rub
a glass rod with flannel
an abonite rod with flannel
a glass rod with silk
Any of the above
The image of an object formed on the retina of the eye is
virtual and upright
virtual and inverted
real and inverted
real and upright
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 method used to separate aluminium from a alumina is
electroplating
electrotyping
electrolysis
distillation
The scientist who first sent electromagnetic waves to distant places was
James Clerk Maxwell
Heinrich Hertz
Thomas Alva Edison
Baird
Which part of the eye photographic camera?
Lens
Iris
Retina
Eyelid
The spectrum of white light can be studied by
a microscope
a telescope
a stereoscope
a spectroscope
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
When light travels from one medium to another there is a change in its
velocity
wavelength
frequency
Both (a) and (b) above
Acoustics' la a branch or study dealing with
historical sites
architecture
sound
trigonometry
Photoelectric cell is a device which converts
light energy into electrical energy
electrical energy into light energy
magnetic energy into electrical energy
electrical energy into mechanical energy
If an empty cylinder Is half ruled with a liquid, Its centre of gravity is
shifted upwards
shifted downwards
shifted neither upward nor downward
shifted upward or downward depending on the density of the liquid
Choose the scalar quantity from the following physical quantities
force
velocity
acceleration
speed
Who first established the fact that the earth revolves round the sun?
Sir Isaac Newton
Kepler
Copernicus
Ptolemy
The transistor was invented by
Marconi
Baird
John Bardeen, Walter H. Brattain and William Shockley
Edison
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
X-rays were discovered by
Wilhelm Roentgen
WO Coolidge
Henry Cavendish
William Watson
Nuclear fusion is a process in which
the atoms and molecules lose their identity
nucleus is split into fragments
the nuclear reaction between two light atomic nuclei results in the formation of a heavier nucleus with release of a large quantity of nuclear energy in the process
absorption of neutron by a nucleus
The study of astronomy include a
astrology
astrophysics
astrometry
Both (b) and (c) above
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
Heat transfer
cools the body that transfers it
heats the body that absorbs the heat
may change the physical state of the substance
All the above