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Find ratio of crictical frequency for reflection of radiowaves from ` E , F_(1) and F_(2)` layers in ionosphere of earth's atmosphere having electron density ` 2 xx 10^(11) , 3 xx 10^(11) and 8 xx 10^(11) m^(-3)` respectively.

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The correct Answer is:
` 1.41 : 1.72 : 2.83`
`v_(c ) = 9 (N_(max))^(1//2) i.e. v_( c ) prop ( N_(max))^(1//2)`
`:. v_(CE) : v_( CF_(1)) : v_(CF_(2))`
`= (2xx 10^(11))^(1//2) : ( 3 xx 10^(11))^(1//2) : ( 8 xx 10^(11))^(1//2)`
` = 2^(1//2) : 3^(1//2) : 8^(1//2) = 1.41 : 1.72 : 2.83`
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