Neon gas is generally used in the sign boards .if it emits strongly at 616 nm calculate (a ) the frequency of emission ( b) distance traveled by this radiation in 30 s (c ) energy of quantum and ( d) number of quanta present if it produces 2 J of energy .

Explanation

(a ) Frequency of emission
`v=(c )/(lambda) = (3.0 xx 10^ (8) ms^(-1))/( 616 xx 10^(9) m)`
( b) Distance traveled by this radiation in 30 s (d )
d= velocity of light `xx ` time
`=3.0 xx 10^(8) ms^(-1) xx 30 s`
`=9.0 xx 10^(9) m`
=`900 ` caror meter = `(xx 10^(8) km)`
(c ) Quantum energy (E ) :
`E= (hc )/( lambda ) = (6.626 xx 10^(34) J s 3.0 xx 10^(8) ms^(-1))/( 616 xx 10^(9) m)`
(d ) Number of quanta in 2 J of energy (N ) :
N= `("total energy ")/(" 1 quantum energy ") = (2J )/( 3.23 xx 10^(19))`
`=6.192 xx 10^(18) ` Number of quantum