Sound travels fastest in
air
water
iron
vacuum
Correct Answer :
C. iron
Related Questions
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
Lightning is produced when
similar charges of electricity rush towards each other and then get repelled
clouds strike against impurities in air and the friction burns up these impurities
strong opposite charges in different clouds break down the resistance offered by the intervening air
water vapour produces electricity in the clouds
The overhead wires supported by high towers in the grid system carry
alternating current of very high frequency
alternating current of very high voltage
a very large direct current
a high voltage direct current
The speed at which light travels in vacuum is
3 x 107 ms-1
5 x 108 ms-1
3 x 104 kms-1
3 x 108 ms-1
Which metal is used in storage batteries?
Copper
Lead
Tin
Iron
The weight of a body is
maximum at the equator
minimum at the equator
minimum at the poles
the same everywhere
Electron-volt is a unit of
power
velocity
energy widely used in nuclear physics
number of electrons
The colour of the light which travels through glass with minimum speed is
red
violet
green
yellow
The study of astronomy include a
astrology
astrophysics
astrometry
Both (b) and (c) above
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
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
Mercury does not stick to glass because
cohesive forces between the mercury molecules are greater than adhesive forces between mercury and glass molecules
the adhesive forces between mercury and glass molecules are greater than the cohesive forces
both the cohesive and adhesive forces are equal
None of the above
Which mirror is used as a rear view mirror in Vehicles?
Parabolic
Convex
Concave
Plain
Increase in pressure
has no effect on the boiling point of a liquid
raises the boiling point of a liquid
lowers the boiling point of a liquid
increases the volume of a liquid
The tiniest of the stars belong to the group known as
Giant stars
White Dwarf stars
Neutron stars
Super-giant stars
When ice melts, Its volume
decreases
increases
remains the same until all the ice has melted and then increases
remains the same
Cosmic rays contain
protons and electrons
alpha particles
gamma rays
All the above
The colour of a star is an indication of its
distance from the earth
age
temperature
size
Stars twinkle because of
refraction of light from them through air
reflection
absorption
All the above
The Solar System lies near the edge of a galaxy known as
The Milky Way
Radio Galaxy
Andromeda Nebula
Magellanic Clouds
The filament lamp is an example for
fluorescence
incandescence
both (a) and (b)
None of these
The unit of power in SI is
Joule
Newton
Joule/Sec
Erg/Sec
The transistor was invented by
Marconi
Baird
John Bardeen, Walter H. Brattain and William Shockley
Edison
The study of astronomy include a
astrology
astrophysics
astrometry
Both (b) and (c) above
Diamond shines because of its
purity
hardness
high density
high refractive index and low critical angle
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
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
The Indian Satellite System used for domestic communications, television and meteorology is known as
INSAT
Bhaskara
Aryabhatta
All the above
When a charged rod is brought near a collection of small pith balls, the balls
will jump rapidly up and down for a short time
will remain unaffected
Both (a) and (b) above
It will produce electric shock
The maximum displacement of the particle in a mechanical wave motion is known as
amplitude
vibration
frequency
phase