When light passes from air to glass, its velocity in glass
increases
decreases
remains unchanged
first decreases then increases
Correct Answer :
B. decreases
Related Questions
Ultrasonic waves are used
in medical and surgical diagnosis
in testing the quality of the linings and pads used in vehicles and aircraft brakes
to clean surgical instruments, jewellery and similar articles
All the above
If you want to open a door with les difficulty you push it
at the middle
at a point away from the hinge (near the rim)
near the hinge
None of the above
The shadow below a tree has bright spots in it because
light comes through circular gaps between the leaves
the leaves are circular
the rays bend to form circular spots
the gaps between the leaves act as pin holes
The brightest planet in the Solar System is
Jupiter
Mercury
Venus
Sirius
Electromagnets are used in
the telephone ear piece
the telegraph
the electric bell
All the above
A device used to measure heights above sea level is known as
altimeter
anemometer
dilatometer
potentiometer
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
A projectile is fired at an angle with the horizontal with a small velocity. Its horizontal range will be maximum when the angle with the horizontal is
0°
30°
45°
60°
Who discovered that the Cree Call acceleration Is the same for any object at a given place?
Newton
Pascal
Archimedes
Galileo
X-rays are
deflected by electric field
deflected by magnetic field
slightly deflected by electric field and magnetic field
not deflected by electric and magnetic fields
Separating particles from a suspension is effected by
centrifugal force
frictional force
gravitational force
distillation
The velocity of sound in air
increases as the square root of the absolute temperature
decreases with temperature
is independent of temperature
None of these
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
The largest reserve of radioactive element which can be used in a nuclear reactor has been found in India, The name of the element is
Thorium
Uranium
Plutonium
Radium
In a freezer ice cubes will be formed more quickly in trays made of
rubber
plastic
aluminium
wood
A man stands in a lift which accelerates upwards. The resultant reaction force on the floor of the lift is
greater than the weight of the man
less than the weight of the man
same as the weight of the man
zero
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
A body has fallen from a height. Just before touching the pound it has
lost all its potential energy and gained an equivalent amount of kinetic energy
gained potential energy and lost kinetic energy
gained kinetic energy as well as potential energy
lost kinetic energy as well as potential energy
The device for tracking and locating the position of a moving object in space is called
Space ship
Lunar module
Radar
Rocket
The characteristics of a musical note are
loudness
pitch
quality or timbre
All the above
When a whistling engine approaches a person standing on the platform, the frequency or the note
appears to increase
appears to decrease
does not change at all
first increases then decreases
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
When ice melts, Its volume
decreases
increases
remains the same until all the ice has melted and then increases
remains the same
The inside of both the walls of a thermos flask is silvered i.e., on the vacuum side in order to reduce heat loss by
convection
radiation
conduction
All the three
Which of the following can produce electricity?
resistor
thermocouple
light bulb
neon tube
The rings of Saturn were discovered by
Galileo
Bhaskara
Aryabhatta
Ptolemy
When a swing is drawn to a side Its potential energy In relation to the earth
increases
decreases
remains the same
is constant
The orbit of Venus lies between those of
Mercury and Earth
Earth and Mars
Mars and Saturn
Mars and Jupiter
A man weighing 50 kg floats on water in a lake. His apparent weight is
50 kg
45 kg
zero
150 kg
The resistance of a wire depends on
the material of the wire
the length of the wire
the cross section of the wire
All the above