JEE MAIN - Chemistry (2011 - No. 28)
A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emissions is at
680 nm, the other is at :
325 nm
743 nm
518 nm
1035 nm
Maelezo
Here a photon is divided into two photons of different wavelength.
According to the law of conservation of energy,
Energy of photon before dividing into two parts = Energy of first photon + Energy of second photon
$${{hc} \over \lambda } = {{hc} \over {{\lambda _1}}} + {{hc} \over {{\lambda _2}}}$$
$$ \Rightarrow {1 \over \lambda } = {1 \over {{\lambda _1}}} + {1 \over {{\lambda _2}}}$$
$$ \Rightarrow {1 \over {355}} = {1 \over {680}} + {1 \over {{\lambda _2}}}$$
$${\lambda _2} = 742.77$$ nm = 743 nm
According to the law of conservation of energy,
Energy of photon before dividing into two parts = Energy of first photon + Energy of second photon
$${{hc} \over \lambda } = {{hc} \over {{\lambda _1}}} + {{hc} \over {{\lambda _2}}}$$
$$ \Rightarrow {1 \over \lambda } = {1 \over {{\lambda _1}}} + {1 \over {{\lambda _2}}}$$
$$ \Rightarrow {1 \over {355}} = {1 \over {680}} + {1 \over {{\lambda _2}}}$$
$${\lambda _2} = 742.77$$ nm = 743 nm