72 questions · self-marked practice — reveal the answer and mark yourself.
A double star is a system of two stars rotating about their centre of mass only under their mutual gravitational attraction. Let the star have mass m and 2m and their separation be l. Their time period of rotation about their centre of mass will be proportional to
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(a) |
(b) l |
(c) |
(d) |
(d) 
A planet which is born sister of earth is
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(a) Mercury |
(b) Venus |
(c) Mars |
(d) Jupiter |
(b) Venus
Mass of earth has been determined through
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(a) Use of Kepler's |
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(b) Sampling the density of earth's crust and using R |
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(c) Cavendish's determination of G and using R and 'g' at the surface |
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(d) Use of periods of satellites at different heights above earth's surface |
(c) Cavendish's determination of G and using R and 'g' at the surface
A planet of mass M has a satellite of mass m, revolving around the planet in a circular orbit of radius r and time period T. The mass (M) of the planet is
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(a) |
(b) |
(c) |
(d) |
(a) 
Which of the planet is brightest
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(a) Mercury |
(b) Venus |
(c) Mars |
(d) Jupiter |
(b) Venus
A galaxy is observed to be moving with a velocity of 8600 km-sec–1. If it is at a distance of 430 million light year from us, Hubble constant and corresponding age of the universe are respectively
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(a) 2 |
(b) 2 |
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(c) |
(d) None of these |
(a) 2 
, 1.49 
Assertion : Moon is seen as it partly reflects the sun light falling on it
Reason : Moon is a satellite of earth. It does not emit light of its own
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.
Assertion : Sun is at the galactic centre C of the milky way
Reason : All planets of solar system revolve around the sun.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If assertion is false but reason is true. |
(d) If assertion is false but reason is true.
Assertion : There is no atmosphere on moon
Reason : Escape velocity at the surface of moon is low.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.
Assertion : A star which appears blue will be much hotter than the sun
Reason : It is based on Wien's law
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.
Assertion : The comet do not obey Kepler's laws of planetary motion
Reason : The comet do not have elliptical orbit
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
The difference in the lengths of a mean solar day and a sidereal day is about
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(a) 1 min |
(b) 4 min |
(c) 15 min |
(d) 56 min |
(b) 4 min
Suppose a planet goes around Sun with a linear speed twice as fast that of earth. What will be it's orbit size as compared to that of earth ? (Radius of earth = R)
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(a) R / 4 |
(b) R / 2 |
(c) R |
(d) 2R |
(a) R / 4
The percentage of Sun's total energy which reaches the earth's surface is
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(a) 10–7 % |
(b) 10–6 % |
(c) 10–3 % |
(d) 10–2 % |
(a) 10–7 %
A planet of mass m moves in an ellipse around the sun of mass 
so that its maximum and minimum distances are 
and 
respectively. The angular momentum of the planet relative to the centre of the sun is
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(a) |
(b) |
(c) |
(d) |
(b) 
Fraunhofer lines of the solar system is an example of
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(a) Emission spectrum |
(b) Emission band spectrum |
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(c) Continuous emission spectrum |
(d) Line absorption spectrum |
(c) Continuous emission spectrum
Consider a binary star system consisting of two stars of masses 
and 
separated by a distance of 30 AU with a period of revolution equal to 30 years. If one of the two stars is 5 times farther from the centre of mass than the other. The masses of the two stars in terms of solar masses are
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(a) 5, 15 |
(b) 25, 5 |
(c) 25, 10 |
(d) 7, 25 |
(b) 25, 5
Assertion : A pulsor is a source of radio waves which change in terms of intensity at regular interval of time
Reason : A pulsor is a rotating neutron star
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
A bright star is indicated to have a brightness magnitude of – 5 compared to a star of brightness zero magnitude. It means that this star compared to the reference star of zero brightness is
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(a) 100 times less bright |
(b) 5 times more bright |
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(c) 5 times less bright |
(d) 100 times more bright |
(d) 100 times more bright
There are certain types of stars called visible stars which undergo periodic change in their light output. If such a star quadruple it's light output, how much does it's magnitude change
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(a) – 1.25 |
(b) – 1.5 |
(c) – 1.75 |
(d) – 2 |
(b) – 1.5
A particular emission line, detected in the light from a galaxy, has a wavelength 
, where 
is the proper wavelength of the line. The galaxy distance from us
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(a) 1.6 |
(b) 0.97 |
(c) 2.4 |
(d) 1.62 |
(a) 1.6 
Assuming that the dimmest visible star to the naked eye has a magnitude of about 6. Brightness of planet Venus (magnitude = – 4) w.r.t. this star is
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(a) 10,000 times brighter |
(b) 2000 times brighter |
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(c) 15000 times brighter |
(d) 4000 times brighter |
(a) 10,000 times brighter
Assertion : The stars twinkle while the planets do not.
Reason : The stars are much bigger in size than the planets.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
Hubble's law is related with
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(a) Comet |
(b) Speed of galaxy |
(c) Black hole |
(d) Planetary motion |
(b) Speed of galaxy
The condition for a uniform spherical mass m of radius r to be a black hole is [G = gravitational constant and g = acceleration due to gravity]
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(a) |
(b) |
(c) |
(d) |
(c) 
The colour of a star is an indication of its
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(a) Weight |
(b) Distance |
(c) Surface temperature |
(d) Size |
(c) Surface temperature
Surface temperature of the sun is of the order of
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(a) 5000 K |
(b) 7000 K |
(c) 6000 K |
(d) 12000 K |
(c) 6000 K
Great bear is a
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(a) Star |
(b) Galaxy |
(c) Constellation |
(d) Planet |
(c) Constellation
Speed of recession of galaxy is proportional to it's distance
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(a) Directly |
(b) Inversely |
(c) Exponentially |
(d) None of these |
(a) Directly
The galaxies are moving away from each other. It is explained by
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(a) White dwarf star |
(b) Red shift |
(c) Neutron star |
(d) None of these |
(b) Red shift
In determining the temperature of a distant star, one makes use of
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(a) Kirchhoff's law |
(b) Stefan's law |
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(c) Wien's displacement law |
(d) None of these |
(c) Wien's displacement law
Smaller pieces of heavy stones and metals which on entering earth's atmosphere burns out are
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(a) Comets |
(b) Meteorites |
(c) Asteroids |
(d) All of these |
(b) Meteorites
Which one of the following is known as Saptarishi
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(a) Orion |
(b) Ursa major |
(c) Ursa minor |
(d) Scorpion |
(b) Ursa major
Which one of the following planet has the longest day
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(a) Venus |
(b) Mars |
(c) Mercury |
(d) Earth |
(a) Venus
The tail of the comet is due to
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(a) Vaporisation of water on the comet |
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(b) Sublimation of vapour in the comet |
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(c) Cooling of water in the comet |
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(d) Vaporisation of heat in the comet |
(a) Vaporisation of water on the comet
The motion of planets in the solar system is an example of conservation of
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(a) Mass |
(b) Momentum |
(c) Angular momentum |
(d) Kinetic energy |
(c) Angular momentum
When original mass of star is greater than 5 M (M = mass of the sun). The death of this star will give rise to
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(a) White dwarf |
(b) Black hole |
(c) Quasars |
(d) Nebula |
(b) Black hole
Albedo is maximum for
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(a) Pluto |
(b) Venus |
(c) Earth |
(d) Mercury |
(b) Venus
Two stars P and Q are observed at night. Star P appears reddish while, star Q is white. From this we conclude
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(a) Temperature of Q is higher than that of P |
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(b) Temperature of Q is lower than that of P |
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(c) Star Q is at the same distance at that of star P |
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(d) Star P is farther than star Q |
(a) Temperature of Q is higher than that of P
How does the red shift confirms that the universe is expanding
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(a) Due to Wien's law |
(b) Due to Stefan's law |
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(c) Due to Kirchhoff's law |
(d) Due to Doppler's effect |
(d) Due to Doppler's effect
Which of the following helps us in the determination of the temperature of sun
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(a) Kirchhoff's law |
(b) Maxwell Boltzmann law |
|
(c) Planck's law |
(d) Stefan's law |
(d) Stefan's law
Meteors are
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(a) Small stars |
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(b) Burnt pieces of comets that fall on earth |
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(c) Comets without tails |
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(d) None of these |
(b) Burnt pieces of comets that fall on earth
'Albedo' is
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(a) Reflecting power of a heavenly body |
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(b) Transmitive power of a heavenly body |
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(c) Absorptive power of a heavenly body |
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(d) Refracting power of a heavenly body |
(a) Reflecting power of a heavenly body
A star which appears blue will be
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(a) As hot as the sun |
(b) Cooler than the sun |
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(c) Very cold indeed |
(d) Much hotter than the sun |
(d) Much hotter than the sun
The sun emits a light with maximum wavelength 510 mm while another star X emits a light with maximum wavelength of 350 nm. What is the ratio of surface temperature of sun and the star X
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(a) 2.1 |
(b) 0.68 |
(c) 0.46 |
(d) 1.45 |
(b) 0.68
An extremely hot star would appear to be
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(a) Red |
(b) Blue |
(c) Yellow |
(d) Orange |
(b) Blue
Which of the nine planets is nearest to sun
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(a) Venus |
(b) Mercury |
(c) Mars |
(d) Jupiter |
(b) Mercury
The length of Milky way is
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(a) 100,000 light years |
(b) 10,000 light years |
(c) 1000 light years |
(d) 100 light years |
(a) 100,000 light years
Period of revolution increases in the order of
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(a) Saturn, Uranus, Venus |
(b) Mars, Saturn, Pluto |
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(c) Mercury, Neptune, Mars |
(d) Mars, Jupiter, Venus |
(b) Mars, Saturn, Pluto
Towards the centre of sun
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(a) Density decreases |
(b) Pressure decreases |
|
(c) Temperature decreases |
(d) Density and pressure increases |
(d) Density and pressure increases
The hottest planet of solar system is
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(a) Mars |
(b) Mercury |
(c) Venus |
(d) Pluto |
(b) Mercury
Hubble's law states that the velocity with which the 'milky way' is moving away from the earth is proportional to
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(a) Square of the distance of the milky way from the earth |
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(b) Distance of milky way from the earth |
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(c) Mass of the milky way |
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(d) Product of the mass of the milky way and its distance from the earth |
(b) Distance of milky way from the earth
According to the pulsating theory the expansion and contraction of the universe repeats after every
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(a) 11 years |
(b) 8 billion years |
(c) 8 million years |
(d) 80 billion years |
(d) 80 billion years
Which of the following planets have rings around it
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(a) Uranus |
(b) Mars |
(c) Jupiter |
(d) Saturn |
(d) Saturn
There is no atmosphere on moon because
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(a) There is no vegetation |
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(b) The escape velocity at its surface is very low |
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(c) Diffusion constant of gases is high |
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(d) There is vacuum in space |
(b) The escape velocity at its surface is very low
Which of the following is coldest planet
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(a) Mercury |
(b) Pluto |
(c) Earth |
(d) Venus |
(b) Pluto
Venus appears brighter than other stars because
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(a) It is heavier than other planets |
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(b) Its density is more than other planets |
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(c) It is nearer to earth in comparison to other planets |
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(d) Nuclear fusion takes place at its surface |
(c) It is nearer to earth in comparison to other planets
Sun radiates continuously and maintains its brightness because
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(a) Helium is converted into iron in its core |
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(b) Of fusion of hydrogen nuclei into helium |
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(c) Fusion of helium in hydrogen |
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(d) Burning of carbon, in its core |
(b) Of fusion of hydrogen nuclei into helium
Asteroids are
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(a) Small planets |
(b) Shooting stars |
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(c) Found in a belt between Earth ad Venus |
(d) None of these |
(a) Small planets
Source of Sun's energy is
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(a) Burning of hydrogen |
(b) Fission reactions involving hydrogen |
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(c) Fusion reactions involving hydrogen |
(d) Some other source |
(c) Fusion reactions involving hydrogen
Black hole is a
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(a) Hole in the ozone layer of atmosphere |
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(b) Hole in earth's centre |
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(c) Highly dense matter available in the atmosphere |
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(d) Hole in troposphere |
(c) Highly dense matter available in the atmosphere
CO2 gas is found in which of the following pairs of the planet
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(a) Earth and Mercury |
(b) Mercury and Saturn |
|
(c) Venus and Saturn |
(d) Venus and Mars |
(d) Venus and Mars
The solar constant on the surface of the earth is S. What will be its value on the surface of another planet which is about 5.3 A.U. away from sun
|
(a) |
(b) |
(c) 5.3 S |
(d) (5.3)2 S |
(b) 
Hubble showed that the universe as a whole is expanding and the distant stars are receding from us. The spectral line from a star, when compared with the corresponding line from an source will then show
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(a) A shift in frequency towards the red end |
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(b) A shift in frequency towards the violet end |
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(c) No shift in frequency at all |
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(d) A shift in frequency towards the violet end as well as a decrease in intensity |
(a) A shift in frequency towards the red end
The age of universe is believed to be
|
(a) 1 billion years |
(b) 10 billion years |
(c) 10-20 billion years |
(d) 1000 billion years |
(c) 10-20 billion years
A study of binary stars is most helpful in
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(a) Finding their distances |
(b) Finding their temperature |
|
(c) Finding their masses |
(d) Verifying Newton's force law of gravitation |
(d) Verifying Newton's force law of gravitation
A group of bright and faint stars is called
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(a) Galaxy |
(b) Comet |
(c) Black hole |
(d) Constellation |
(d) Constellation
According to modern astronomers into how many constellations, the whole sky is divided
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(a) 1011 |
(b) 88 |
(c) 880 |
(d) 5000 |
(b) 88
Which of the following theories is the most satisfactory about the origin of the universe
|
(a) Big Bang theory |
(b) Pulsating theory |
(c) Steady state theory |
(d) None of these |
(a) Big Bang theory
Assertion : Red shift confirms that the universe is expanding
Reason : Wavelength of red light is maximum in the visible region
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.
The wavelength of maximum energy, released during an atomic explosion, was 2.93 × 10–10 m. Given that the Wien's constant is 2.93 × 10–3 m K, the maximum temperature attained must be of the order of
|
(a) 10–7 K |
(b) 107 K |
(c) 10–13 K |
(d) 5.86 × 107 K |
(b) 107 K
The sun revolves around the galaxy with a speed of 250 km/sec and it's radius is 3 × 104 light year. The mass of the milky way is
|
(a) 3 × 1040 kg |
(b) 3 × 1041 kg |
(c) 5 × 1040 kg |
(d) 6 × 1041 kg |
(b) 3 × 1041 kg
