The light from the star nearest to the sun reaches the earth in
8 minutes
4.3 years
12 seconds
24 hours
Correct Answer :
B. 4.3 years
Related Questions
When a bullet is fired from a gun
the gun moves forward
the gun jumps up
the gun does not move
the gun recoils with the same momentum as the bullet
Photoelectric cell is a device which converts
light energy into electrical energy
electrical energy into light energy
magnetic energy into electrical energy
electrical energy into mechanical energy
Water has maximum density at
0° C
-15° C
4° C
15° C
An electric kettle used for boiling hard water has a white scale deposited on its heating element. This consists or
sugar
sodium carbonate
common salt
carbonates of calcium and magnesium
The attraction between similar molecules is called
inertia
adhesion
cohesion
friction
Which of the following revolves round the nucleus in an atom?
protons
electrons
neutrons
positrons
Primary colours are
colours of the rainbow
colours in the spectrum of white light
colours which cannot be produced by mixing other colours
colours found in nature
A rod of brass la held in hand and rubbed with fur. The rod is found to have
no charge
positive charge
negative charge
can't be said
The function of a ruse wire is
to stabilise the voltage
to decrease the current supply
to increase the current supply
to prevent an unduly high current from passing through a circuit
Dioptre is the unit of power of
convex mirrors
concave mirrors
concave lenses
lenses irrespective of types
A boy is swinging a ball attached to a string in a horizontal circle. If the string snaps
the ball will travel towards the centre of the circle and fall down
it will continue to travel along a tangent to the circle at the point the ball was at the time of snapping and finally fall down
it will fall down at the same place where the string breaks
None of these
Light from the sun reaches the earth in
2 minutes
4 minutes
12 minutes
8 minutes
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
The planet that moves fastest around the sun is
Mars
Venus
Earth
Mercury
When a steel ball is placed on the surface of mercury, it does not sink because
of the surface tension of mercury
mercury is a semi-solid
of the high viscosity of mercury
the density of mercury is greater than that of steel
When water is cooled from 4�C to 2�C its density
increases
decreases
remains the same
first increases then decreases
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
For viewing objects placed at a higher level from a position at a lower level, the instrument used' Is known aa
telescope
spectrometer
microscope
periscope
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
We see the sun before it actually rises on the horizon. This is due to
refraction
reflection
total internal reflection
parallax
Photoelectric cell is a device which converts
light energy into electrical energy
electrical energy into light energy
magnetic energy into electrical energy
electrical energy into mechanical energy
When sound waves travel from one medium to another, the quantity which remains unchanged is its
speed
frequency
wavelength
All the above
In compact porous soil, the rising of the water is due to
capillarity
cohesion
adhesion
viscosity
Under similar conditions of temperature and pressure, the velocity of sound is maximum in
helium
argon
hydrogen
oxygen
In an electrical circuit, a fuse is connected
in the live wire
in the neutral wire
in the earth wire
anywhere
The Indian Space Research Organisation (ISRO) is located at
Thumba
Bangalore
Ahmedabad
New Delhi
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
Who first established the fact that the earth revolves round the sun?
Sir Isaac Newton
Kepler
Copernicus
Ptolemy
The speed of sound in a medium depends upon the properties of the medium such as
its density
its temperature
its elasticity
All the above
In the visible spectrum which colour has the shortest wavelength?
Red
Blue
Yellow
Violet