Tag: elementary ideas of astronomy

Questions Related to elementary ideas of astronomy

Following factors may be responsible for the colour of a star.
I. The size of the star
II. The distance of the star from the earth
III. The surface temperature of the star
Which combination is correct?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. III only

  2. II only

  3. I and II only

  4. I, II and III

Show answer
Correct Option: C
Explanation:

Factor responsible for colour of the star is surface temperature of the star it does not depend upon size of the star and distance of star from the earth.

Who is known as father of Modern Indian Astronomy?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. Venkoji Bapu Ketkar

  2. Meghnath Saha

  3. M.K. Vainu Bappu

  4. Dr. S. Chandrashekhar

Show answer
Correct Option: C
Explanation:

Manali Kallat Vainu Bappu or M.K Vainu Bappu is known the father of Modern Indian Astronomy. He along with American astronomer Olin Chaddock Wilson discovered the Wilson-Bapu effect in 1957.  

Thus, the correct answer is 'M.K. Vainu Bappu.'

Suppose an earth satellite, revolving in a circular orbit experiences a resistance due to cosmic dust. Then.

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. Its kinetic energy will increase

  2. Its potential energy will decrease

  3. It will spiral towards the earth and in the process its angular momentum will remain conserved

  4. Both a and b is correct

Show answer
Correct Option: D
Explanation:
The Kinetic energy of the satellite increases in spiral path as it approach the earth so $V$ must increase the total mechanical energy of the satellite decreases due to resistance from conic dust as satellite approaches earth so potential energy decreases.
Thus Kinetic energy increase potential energy decreases.

The Halley's comet appears after every

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. $72$ years

  2. $74$ years

  3. $75$ years

  4. $78$ years

Show answer
Correct Option: C
Explanation:

Halley's comet appears after every  $75$ years.

Halley's Comet is arguably the most famous comet. It is a "periodic" comet and returns to Earth's vicinity about every $75$ years, making it possible for a human to see it twice in his or her lifetime. The last time it was here was in 1986, and it is projected to return in $2061.$

The comet is named after English astronomer Edmond Halley, who examined reports of a comet approaching Earth in $1531, 1607$ and $1682$. He concluded that these three comets were actually the same comet returning over and over again, and predicted the comet would come again in $1758$.

Which is the brightest star visible from earth?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. Sirius

  2. Antares

  3. Vega

  4. Rigel

Show answer
Correct Option: A
Explanation:

The brightest strain the shy is Sirius also known as Dog star or more officially Alpha can is Magon's for its position in constellation canis Major.

What is metrology?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. The study of people's influx to a metropolitan city

  2. The study of earth's atmosphere

  3. The science of measuring

  4. The study of meteors

Show answer
Correct Option: C
Explanation:

Metrology is the scientific study of the atmosphere that focuseson weather processes and forecasting.

The colour of a green leaf, when white light passing through a yellow filter is applied on it is:

evs light and shadow nature and sources of light how light travels path of light elementary ideas of astronomy

  1. black

  2. yellow

  3. red

  4. green

Show answer
Correct Option: A
Explanation:

A yellow filter allows only yellow colour to pass through it. A leaf looks green because leaf reflects green colour and absorbs the rest. Thus, the yellow light passing through the filter will be absorbed by the green leaf. Thus, no colour will be reflected by the leaf making it appear black.

The path along which light travels is called a ........

evs light and shadow nature and sources of light how light travels path of light elementary ideas of astronomy

  1. ray

  2. line

  3. line segment

  4. none

Show answer
Correct Option: A
Explanation:

The path along which light travels is called a Ray.

A beam of light gets reflected from a plane mirror and a real image is formed. The incident beam should be 

evs light and shadow nature and sources of light how light travels path of light elementary ideas of astronomy

  1. Parallel

  2. Convergent

  3. Divergent

  4. Plane mirror cannot form a real image

Show answer
Correct Option: B
Explanation:

  1. Plane mirrors don't usually form real images They form virtual images of real objects. However, things can be arranged so that a plane mirror does form a real image. A convergent light beam can do this. So the answer is "convergent"

  2. When at convergence point, a convergent beam of light is incident on the plane mirror, a real image is formed at the point

During reflection when light gets reflected form a surface 

evs light and shadow nature and sources of light how light travels path of light elementary ideas of astronomy

  1. it selects the path that takes the least time

  2. it selected the path that takes the maximum time

  3. it selects the shortest path

  4. none of these

Show answer
Correct Option: A
Explanation:

it selects the path that takes the least time.