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Neon gas is generally used in the sign b...

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

Text Solution

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`lamda = 616 nm = 616 xx 10^(-9) m`
(a) Frequency, `v = (c)/(lamda) = (3.0 xx 10^(8) ms^(-1))/(616 xx 10^(-9) m) = 4.87 xx 10^(14) s^(-1)`
(b) Velocity of the radiation `= 3.0 xx 10^(8) ms^(-1)`
`:.` Distance travelled in `30s = 30 xx 3 xx 10^(8) m = 9.0 xx 10^(9) m`
(c) `E = hv = h (c)/(lamda) = ((6.626 xx 10^(-34) Js) xx 3.0 xx 10^(8) ms^(-1))/(616 xx 10^(-9) m) = 32.27 xx 10^(-20)J`
(d) No. of quanta in 2J of energy `= (2)/(32.27 xx 10^(-28)) = 6.2 xx 10^(18)`
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