Tag: elementary ideas of astronomy

Questions Related to elementary ideas of astronomy

Light waves:

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

  1. require air or another gas to travel through

  2. require an electric field to travel through

  3. require a magnetic field to travel through

  4. can travel through perfect vacuum

Show answer
Correct Option: D
Explanation:

Light is an electromagnetic wave which is transverse in nature. It does not require any material medium to pass through and can travel through vacuum.

Which of the following is a non-luminous body ?

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

  1. Sun

  2. Moon

  3. Candle flame

  4. Electric lamp

Show answer
Correct Option: B
Explanation:

Moon does not emit its own light. It reflects the light incident on it from the Sun. So, Moon is a non-luminous body.

Find out the only wrong statement in the following:

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

  1. Light travels with a speed greater than that of sound

  2. Light cannot travel through vacuum

  3. Light travels in a straight line

  4. Light has no weight

Show answer
Correct Option: B
Explanation:

Light is an electromagnetic wave which is transverse in nature. So, it does not require any material medium to pass through. Light, thus, can travel through vacuum.

A green leaf placed in a dark room is illuminated by red light. The leaf will appear to be :

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

  1. green

  2. red

  3. yellow

  4. black

Show answer
Correct Option: D
Explanation:

A green leaf can only reflect green light, so when red light is incident on it, the leaf will not be able to reflect any light making it look black

The path along which light travels in a homogenous medium is called the

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

  1. beam of light

  2. ray of light

  3. pencil of light

  4. none of these

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Correct Option: B
Explanation:

Definition:- The path a traced by light is called a ray of light. 

We can see an object from every direction due to ____________ of the incident light ray on the object.

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

  1. regular refraction

  2. regular reflection

  3. irregular reflection

  4. none of these

Show answer
Correct Option: C
Explanation:

Irregular reflection makes us see all the objects and everything around us. If light gets regularly reflected then every object would act like a mirror and our surroundings would be illuminated. This would have a blinding effect on eyes making it harder for us to see.

A leaf which contains only green pigments, is illuminated by a laser light of wave length 0.6328 $\mu$ m. It wound appear to be:

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

  1. Brown

  2. Black

  3. Red

  4. Green

Show answer
Correct Option: B
Explanation:

0.6328 $\mu m$ = $6328 \mathring A$
This is wavelength of red colour. So, this light will be absorbed by green pigments. 
The leaf will appear black.

What is known as an eclipse?

physics effects of light eclipses elementary ideas of astronomy shadow formation and optical medium

  1. Astronomical event when one celestial body partially or totally cover another celestial object

  2. Astronomical event when one celestial body cover another meteor

  3. Astronomical event when one meteor partially or totally cover another meteor

  4. None

Show answer
Correct Option: A
Explanation:

An eclipse is an event where one heavenly body compeletely or partially blocks the light from the other heavenly body.

Which type of eclipse is known when Earth, Moon and Sun doesn't align in straight line and Moon only partially covers sun?

physics effects of light eclipses elementary ideas of astronomy shadow formation and optical medium

  1. Total Solar Eclipse

  2. Partial Solar Eclipse

  3. Annular Solar Eclipse

  4. None

Show answer
Correct Option: B
Explanation:

When Moon is between the Sun and the Earth but doesn't align in a straight line results in a partial solar eclipse.

Partial Solar Eclipse is known when Earth, Moon and Sun doesn't align in straight line and Moon only partially covers sun.

State whether the given statement is true or false :

Looking at a solar eclipse without any protective eyewear can severely harm your eyes. 

physics effects of light eclipses elementary ideas of astronomy shadow formation and optical medium

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Looking at a solar eclipse without any protective eyewear can severely harm your eyes. It is safe to look at the Sun during the total solar eclipse since Moon cover the Sun totally. However, it is not safe to look at the Sun during solar eclipse, other than the total solar eclipse.