If amplitude of electric field in the incident light is made 25 V / m , how much | TestHub

Passage / Comprehension

Consider a classic experiment on the photoelectric effect in which a monochromatic plane wave of light falls on a metal plate of area $66.3 cm^{2}$ at the angle $3 0^{\circ}$ as shown in the figure. Electric field in the light wave varies according to equation $E = E_{0} cos (ω t + ϕ_{0})$ , where amplitude is $E_{0} = 15 V / m$ , angular frequency is $ω = 9.5 \times 1 0^{15} rad / s$ and $ϕ_{0}$ is some initial phase angle. For a plane wave, the density u of electromagnetic energy is given by the equation $u = \frac{1}{2} ε_{0} E_{0}^{2} . [h = 6.63 \times 1 0^{- 34} SI, ϵ_{0} = 8.85 \times 1 0^{- 12} SI]$ \\

\\ Dependence of photoelectric current I on voltage V applied between the electrodes is shown by a graph.\\

If amplitude of electric field in the incident light is made $25 V / m$ , how much will the saturation current become, in micro-Amperes?

Answer:

16.66

Solution:

Frequency and work-function unchanged ⇒ saturation current depends directly on intensity, and $I \propto (amplitude)^{2}$

$\frac{i _{2}}{i _{1}} = (\frac{25}{15})^{2} = \frac{25}{9} \Rightarrow i_{2} = 6 \times \frac{25}{9} = \frac{50}{3} = 16.67 μ A$

Physics - Modern Physics Question with Solution | TestHub

Doubts & Discussion