IIT JEE , AIEEE Forum - Physics , Mechanics

v_gurucharan

AT WHAT HEIGHT A PEAK IONIZATION OCCURS???

elastiboysai

i dont get ur question , can u be more clear?

v_gurucharan

sry, i too didn't understand this!!!
but the question is this !!!
options:
a) at gr8 heights b) at intermediate height

c) ht does not matter d)close to earth

elastiboysai

a) at great heights
i think its bcoz ionosphere is the uppermost layer in the atmosphere.
The F region or the Appleton layer has extreme ultraviolet (UV) (10-100 nm) solar radiationcapable of ionizing atomic oxygen too.
at lower heights, extent of ionization decrese

elastiboysai

Just somthing more to add on:
Solar radiation, acting on the different compositions of the atmosphere with height, generates layers of ionization:

D layer,Elayer,Es layer,F layer
D layer
is 50-90 km abov earth's surface
here ionization is due to Lyman series, mainly oxidising NO
Recombination is high in the D layer, thus the net ionization effect is very low and as a result high-frequency (HF) radio waves aren't reflected by the D layer. The frequency of collision between electrons and other particles in this region during the day is about 10 million collisions per second.

E layer
is the middle layer, 90 km to 120 km above the surface of the Earth. Ionization is due to soft X-ray (1-10 nm) and far ultraviolet (UV) solar radiation ionization of molecular (O₂). This layer can only reflect radio waves having frequencies less than about 10 MHz. It has a negative effect on frequencies above 10 MHz due to its partial absorption of these waves.

Es layer or sporadic E-layer.
Sporadic e propogation is characterized by small clouds of intense ionization, which can support radio wave reflections from 25 ? 225 MHz.

and i hv already told abt F layer

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