When light travels from one medium to another there is a change in its
velocity
wavelength
frequency
Both (a) and (b) above
Correct Answer :
D. Both (a) and (b) above
Related Questions
In a hydraulic pressure
force on each square centimetre of the small piston is less than the force on each square centimetre of the large piston
the distance the small piston moves is equal to the distance the large piston moves
applied pressure is equally transmitted throughout the liquid in all directions
force acting on small piston is equal to the force acting on large piston
Diamond shines because of its
purity
hardness
high density
high refractive index and low critical angle
Photocells are used
in burglar alarms
in automotive devices for light switches
television cameras
All the above
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
Holography is the technique of
taking photos of various objects
recording and reproducing three dimensional images
tracing out planets and stars in the sky
transmitting light waves
It is more difficult to walk on ice than on a concrete road because
there is very little friction between the ice and feet pressing it
ice is soft when compared to concrete
there is more friction between the ice and feet
None of the above
In an electrical circuit, a fuse is connected
in the live wire
in the neutral wire
in the earth wire
anywhere
The distance between two bodies is halved. Now the force of attraction between them will be
half
one fourth
four times
two times
A wire conveying a current deflects a pivoted magnetic needle. This was discovered by
Marconi
Oersted
Faraday
Ohm
The Cact that the compass needle does not point true north was observed first by
Sir Isaac Newton
Columbus
Archimedes
Thomas Alva Edison
The temperature, surface features, length of days and nights of a planet depend on
its atmosphere
its distance from the sun
its rotation
All the above
Which is the densest planet of the solar system?
Sun
Jupiter
Mercury
Earth
At temperature near OK, (zero kelvin) metals such as lead and tin become
insulators
semiconductors
superconductors
condenser
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
For an electron orbiting in a hydrogen atom, the necessary centripetal force keeping it in orbit is provided by
the electrical attraction between the negatively charged electron and the positively charged porton
the high speed of the electron
the low speed of the electron
gravity
Solar radiation is preferred to other sources of energy because
it is practically inexhaustible
it is the cheapest form of energy
it does not cause pollution
All of the above
Sound waves In 'air travel faster if
frequency is higher
wavelength is smaller
pitch is smaller
air is warmer
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
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
The leader of the team who succeeded in constructing the first nuclear reactor (an atomic pile) in the world was
Albert Einstein
Enrico Fermi
HJ Bhabha
Sir Isaac Newton
Hydrophone is an instrument used
for measuring relative density of liquids
by ships to pass on messages
for determining the depth of ocean bottoms etc.
by deaf people to aid hearing
The first Indian Satellite launched from a Russian Cosmodrome on April 16, 1975 was named
Bhaskara
Insat I-A
Aryabhatta
SLV-l
The principle of equivalence of mass and energy was established by
Dalton
Rutherford
Einstein
Planck
An electric fan converts
electrical energy into heat energy
electrical energy into mechanical energy
mechanical energy into electrical energy
mechanical energy into heat energy
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
The sun continuously produces an enormous amount of energy. This la due to
nuclear fission
nuclear fusion
chemical combustion
boiling
The force of attraction or repulsion between two charged bodies is directly proportional to the product of the charges and inversely proportional to the square of distance between them. This was propounded by
Coulomb
Gilbert
Volta
Rutherford
The image of an object formed in a plane mirror
is real
is virtual
can be obtained on a screen
is slightly bigger than the object
A simple mercury barometer is found in a slightly slanting position. The atmospheric pressure
is found by measuring the slanting height of the mercury column
is given by the vertical height
cannot be measured with it
u) can be measured by both the methods described above
Solids have definite shapes. This is because
the forces of cohesion of the molecules within are very much less in them
the forces of cohesion are very large
the forces of adhesion are large
the forces of adhesion are less