The speed of light is minimum while passing through
air
glass
vacuum
water
Correct Answer :
B. glass
Related Questions
The velocity of sound in air increases with
the rise of temperature
rise of its frequency
decrease in humidity
fall of temperature
In a refrigerator, the refrigerant is
Nitrogen
Oxygen
Chlorine
Freon
What is the minimum velocity required for a rocket to overcome earth's gravity and travel into space?
18 km/sec
11.2 km/ sec
21 km/ sec
35 km/ sec
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
The following are the atmospheric zones above the surface of the earth:
A) Troposphere
B) Ionosphere
C) Stratosphere
D) Exosphere
Select the correct sequence from the earth's surface on the basis of the codes given below:
ACBD
ABCD
CABD
BACD
The sun continuously produces an enormous amount of energy. This is due to
nuclear fission
nuclear fusion
chemical combustion
boiling
A spherical mirror is
a reflecting elliptical portion
a reflecting spherical surface
a parabolic reflecting surface
a flat reflecting surface
The tiniest of the stars belong to the group known as
Giant stars
White Dwarf stars
Neutron stars
Super-giant stars
A boy sitting in a train moving with a uniform velocity drops a coin outside. A man standing outside the train will find the trajectory of the coin to be
a parabola
a horizontal straight line
a vertical straight line
a circle
The numerical reading of the Fahrenheit thermometer of a given temperature
is proportional to that of the Celsius thermometer
is always greater than that of the Celsius thermometer
is always less than that of the Celsius thermometer
may be greater than or less than or equal to that of the Celsius thermometer
The function of a moderator in a nuclear reactor is
to absorb unwanted neutrons
to slow down the fast neutrons to secure more effective hits on other nuclei
to decrease the number of fissile nuclei
to increase the number of fissile nuclei
A small bubble of air deep down in a lake rises up to the top of the lake. The volume of the bubble on coming up will
increase
decrease
will not change
first increase and then decrease
Pieces of camphor placed on water move about rapidly. This is because of
diffusion
viscosity
surface tension
capillarity
The heating element often used in an electric iron is
copper
tungsten
mica
nichrome
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
In hot climatic conditions, the buildings are painted white because
white paint is economical
it does not fade off
it does not crack with higher temperature
white coating is a bad conductor of heat and reflects heat rays that fall on it, thus keeping the inside cool
A bolometer is used to measure
the quantity of heat energy in a body
thermal radiations quantitatively
high temperature
the intensity of sound
The rocket engine is motivated by jet propulsion which uses the famous
Kepler's Laws
Newtonian Third Law of Motion
Bernoulli's Principle
Law of Relativity
The world's first artificial satellite Sputnik I was launched by Russia in
1985
1957
1959
1960
Dioptre is the unit of power of
convex mirrors
concave mirrors
concave lenses
lenses irrespective of types
The instrument used to measure the strength of electric current at a point is
Ammeter
Altimeter
Adrinometer
Anemometer
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
Changing of one element into another element is known as
transmutation
fission
fusion
radioactivity
The device for tracking and locating the position of a moving object in space is called
Space ship
Lunar module
Radar
Rocket
The phenomenon of radioactivity was discovered by
Rutherford
Bohr
Henri Bacquerel
Marie Curie
Body A is kept in contact with body B. Heat will flow from A to B if
the heat content of A is greater than that of B
the temperature of A is greater than that of B
the specific heat of A is greater than that of B
the specific heat of B is greater than that of A
Bats flying in the dark avoid obstacles because
they can see very dearly only in darkness
they produce ultrasonic waves which guide them
their eyes are sensitive to darkness
their eye holes expand in darkness
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
In which of the following will a piece of iron weigh most?
in air
in an atmosphere of oxygen
in an atmosphere of CO2
in vacuum
The spectrum of white light can be studied by
a microscope
a telescope
a stereoscope
a spectroscope