Red Light is used as a dancer signal because
it is pleasing to the eye
it has a traditional colour
it is easily distinguishable
it is most sensitive to the human eye
Correct Answer :
D. it is most sensitive to the human eye
Related Questions
The extremely luminous objects located at the centre of some distant galaxies and which are sources of high energy electromagnetic radiation are known as
Nebulae
Quasars
Meteors
Comets
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
When a body is projected upwards
the time for the upward journey and downward journey are the same
the upward journey takes more time
the downward journey takes more time
Cant be said
The audible range of a normal human ear is frequencies ranging from
10000 to 20000 Hz
50 to 15000 Hz
20 to 20000 Hz
15 to 50000 Hz
In the ramous equation of Einstein E = mc2 , 'c' denotes.
velocity of sound
velocity of light
a constant factor
wavelength of light
Warm air will hold more water vapour than cold air because
it is lighter
it has more water vapour in it
its molecules are close together
its molecules are far apart
The power of a lens is
equal to its focal length
equal to its radius of curvature
equal to the reciprocal of its focal length (in metres)
equal to twice its focal length
The theory that the earth constituted the centre of the universe around which the sun and the planets revolved was propounded by
Copernicus
Ptolemy
Newton
Kepler
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
Pieces of camphor placed on water move about rapidly. This is because of
diffusion
viscosity
surface tension
capillarity
During thunder storm you are travelling in a car. To protect yourself from the lightning you will have to
remain in the car
get out of the car and lie flat in the ground
abandon the car and take shelter under a nearby tree
touch the nearest electric pole
When a ship floats on water, the weight or water displaced is
an indeterminate quantity
equal to the weight of the ship
greater than the weight of the ship
less than the weight of the ship
Moon has no atmosphere because
it has no population
it is quite far off
its surface is full of rocks
its gravity is not sufficient for any atmosphere to hold on to it
A hydrogen bomb is based on
nuclear fusion
nuclear fission
Both (a) and (b) above
Neither (a) nor (b)
The Space Application Centre for training in Satellite Communication Technology is located at
Bangalore
Mumbai
Ahmedabad
New Delhi
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
We see the sun before it actually rises on the horizon. This is due to
refraction
reflection
total internal reflection
parallax
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
To produce beats it is necessary to have two waves
travelling in opposite direction
of slightly different frequencies
of equal wavelength
of equal amplitude
Atoms which have the same atomic number but different mass numbers are called
isobars
isomers
isotones
isotopes
SONAR (Sound Navigation Ranging) is
used by warships and military aircraft to locate enemy submarines
used by ships to determine the depth of water beneath them
a detective device that uses sound to locate under - water objects
All the above
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 temperature below absolute zero for an ideal gas
cannot be attained experimentally
can be attained
is impossible
Does not exist at all
The radius of curvature of a spherical mirror is
equal to half its focal length
equal to its focal length
twice its focal length
not related to its focal length
Which of the following is wrongly matched?
electric current - ampere
resistance - Ohm
electric power - volt
electric charge Coulomb
Besides protons, the nucleus of an atom contains
electrons
neutrons
neutrons and electrons
electrons, neutrons and other particles
Where does the centre of gravity of a rubber ring lie?
on the outer surface
in the inner surface
at the centre of the ring
None of the above
The characteristics of a musical note are
loudness
pitch
quality or timbre
All the above
Water kept in an earthen pot is less cool on rainy days than in summer because during the rainy days
the pores in the pot are closed
rain water stops oozing out from the pores
the water that oozes out does not evaporate quickly because of the large percentage of moisture in the air
surface of the pot becomes damp
The stars that shine brightly then dimly and then brightly are known as
meteors
binaries
variable stars
bright stars