Question 131: Dual Nature of Matter and Radiation

Question

The kinetic energy of emitted electron is E when the light incident on the metal has wavelength $$\lambda$$. To double the kinetic energy, the incident light must have wavelength:

Accepted Answer

$$k = {{hc} \over \lambda } - \phi  = E$$
and, $$2k = {{hc} \over {{\lambda _2}}} - \phi  = 2E$$
$$ \Rightarrow {{hc} \over \lambda } - E = {{hc} \over {{\lambda _2}}} - 2E$$
$$ \Rightarrow {{hc} \over {{\lambda _2}}} = {{hc} \over \lambda } + E$$
$$ \Rightarrow {\lambda _2} = {{hc\lambda } \over {hc + \lambda E}}$$

Answer

$$\frac{\mathrm{hc}}{\mathrm{E} \lambda-\mathrm{hc}}$$

Answer

$$\frac{\mathrm{hc} \lambda}{\mathrm{E} \lambda+\mathrm{hc}}$$

Answer

$$\frac{\mathrm{h} \lambda}{\mathrm{E} \lambda+\mathrm{hc}}$$

Answer

$$\frac{	ext { hc } \lambda}{\mathrm{E} \lambda-\mathrm{hc}}$$

Dual Nature of Matter and Radiation

The kinetic energy of emitted electron is E when the light incident on the metal has wavelength $\lambda$. To double the kinetic energy, the incident light must have wavelength:

Choose the correct answer: