Question

jisko aata he vo solve kr do pls

Answer 1

11) Rainbow is formed due to refraction, dispersion and total internal reflection of sunlight by tiny droplets of water

Answer 2

HOLA friend!!
Rajdeep here.....

Q8. The electronic configuration of an element plays a very important role in determining the position of the element in the periodic table. 

The period, to which an element belongs, is determined by the number of shells present in an atom of the element. The group to which the element belongs, is determined by the number of outer-shell (valence) electrons present in an atom of the element.
For example:
Calcium....
Electronic configuration of Calcium is 2,8,8,2
It is clear that Calcium has four shells and 2 valence electrons.
Thus, Calcium (Ca) belongs to Group 2 of the 4th Period.


Q9. Electronegativity is the phenomenon in which an atom tends to attract the shared pair of electron(s) towards itself.
Nitrogen is an element, whose size is smaller than that of Phosphorus. As a result, the nuclear pull on the valence electrons of Nitrogen is more than that of Phosphorus. So, Nitrogen can more easily attract the shared pair of electron towards itself than Phosphorus can. As a result, nitrogen is more electronegative than phosphorus.


Q10. Long answer, numerical based, I shall ask someone to answer it.


Q11. First, let me define two terms:
Dispersion: Dispersion is the phenomenon by which a polychromatic light splits up into its constituent colours when it enters a denser medium (prism). Dispersion occurs mainly due to difference in the speeds of light of different colours.
Spectrum: After the polychromatic light splits up, when the colours are obtained on the screen, it is called Spectrum.
Now, after rainfall, the water that has fallen as rain on the ground slowly starts evaporating, absorbing its latent heat from the atmosphere. Hence, the atmosphere becomes humid, with huge amount of water vapour.
Each droplet of water vapour acts as a prism, separating two mediums: Air (in the atmosphere) and Water (the water vapours).
Hence, white light from the sun, when enters into these water vapour prisms from air, it splits up into its seven constituent colours (Violet, Indigo, Blue, Green, Yellow, Orange, and Red), and thus rainbow is formed.


Q12. We can see distant and near objects clearly due to Power of Accomodation. Power of Accomodation is the ability of our eye lens to adjust its convexity we can view objects at different distances clearly. To see a distant object, the lens becomes flat (less convex) and vice versa.

The ciliary muscles and suspensory ligaments help in changing the convexity of the lens.

Blind spot is the area from where the optic nerve arises, hence, no photosensitive cells (rods or cones) are present here. Thus, this is the area of zero vision, so no image is formed here.


Q13. I'll ask my friends again to answer you.

Q14. Power of concave lens = -4.5D
Let the Power be P and Focal length of the lens be f

We know, 1/f = P (where f is measured in metres).
Hence, f = 1/P
=> f = 1/4.5
=> f = 0.23 metres.

hence, the focal length of the lens is 0.23m.


Hope my answers are satisfactory...
Thanks!!