question_answer 66)

Neon gas is generally used in the signboards. If it is emitted strongly at 616 nm. Calculate: (a) the frequency of emission (b) distance travelled by the radiation in 30 sec (c) energy of quantum and (d) number of quanta present if it produces 2 J energy.

Answer:

(a) Frequency, \[v=\frac{c}{\lambda }=\frac{3\times {{10}^{8}}}{616\times {{10}^{-9}}}\] \[=4.87\times {{10}^{14}}Hz\] (b) Distance = Speed x time \[=3\times {{10}^{8}}\times 30=9\times {{10}^{9}}m\] (c) \[E=hv=6.626\times {{10}^{-34}}\times 4.87\times {{10}^{14}}=3.227\times {{10}^{-19}}\text{J}\] (d) Let x quanta provides 2J energy \[E=x\times \] energy of 1 quanta \[2=x\times 3.227\times {{10}^{-19}}\] \[x=6.2\times {{10}^{18}}\]