Find the number of photons emitted per second from of source of light which results in a photocurrent with drift velocity of $1.5\ m/s$ in a conductor with cross-section area $0.25\ m^2$ , volume density of electrons $10^{20}\ per \ m^3$ , (Assume that $60\%$ of photons emitted result in electron emission)
Medium
Download our app for free and get started
$ \mathrm{i}=\mathrm{neAV}_{\mathrm{d}} $
$ \Rightarrow \frac{{{{\rm{n}}_{\rm{e}}} \times {\rm{e}}}}{{\rm{t}}} = {10^{20}} \times 1.6 \times {10^{ - 19}} \times 0.25 \times 1.5$
$= 16 \times \frac{1}{4} \times \frac{3}{2}=6 $
$ \Rightarrow \frac{\mathrm{n}_{e}}{\mathrm{t}}=\frac{6}{1.6 \times 10^{-19}} $
$ \Rightarrow \frac{{{{\rm{n}}_{\rm{p}}}}}{{\rm{t}}} = 6.25 \times {10^{19}}\,$ [ Given ${{\rm{ }}\frac{{{{\rm{n}}_{\rm{p}}}}}{{\rm{t}}} \times 60\% = \frac{{{{\rm{n}}_{\rm{e}}}}}{{\rm{t}}}}$]
Download our appand get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
Similar Questions
- 1If $n,\,e,\,\tau $ and $m$ respectively represent the density, charge relaxation time and mass of the electron, then the resistance of a wire of length $l$ and area of cross-section $A$ will beView Solution
- 2An ideal battery of $4\, V$ and resistance $R$ are connected in series in the primary circuit of a potentiometer of length $1\, m$ and resistance $5\,\Omega $ . The value of $R$, to give a difference of $5\, mV$ across $10\, cm$ of potentiometer wire, is: ................ $\Omega$View Solution
- 3For a metallic wire, the ratio $V/i$ ($V = $ the applied potential difference, $i$ = current flowing) isView Solution
- 4A heater $A$ gives out $300\, W$ of heat when connected to a $200\, V$ $d.c.$ supply. Asecond heater $B$ gives out $600\, W$ when connected to a $200\,v$ $d.c$. supply. If a series combination of the two heaters is connected to a $200\, V$ $d.c$. supply the heat output will be ................. $W$View Solution
- 5A metal wire has a resistance of $35 \,\Omega$. If its length is increased to double by drawing it, then its new resistance will be (in $\Omega$)View Solution
- 6A cell having an emf $\varepsilon$ and internal resistance $r$ is connected across a variable external resistance $R.$ As the resistance $R$ is increased, the plot of potential difference $V$ across $R$ is given byView Solution
- 7In the fig. shown for given values of $R_1$ and $R_2$ the balance point for jockey is at $40\, cm$ from $A$. When $R_2$ is shunted by a resistance of $10\,\Omega $, balance shifts to $50\, cm. R_1$ and $R_2$ are $(AB = 1\,m)$View Solution
- 8In the given circuit reading of ideal voltmeter is $\frac{E}{2}$ then internal resistance of cell is ............. $\Omega$View Solution
- 9View SolutionElectric power is transmitted over long distances through conducting wires at high voltage because
- 10In meter bridge experiment for measuring unknown resistance ' $S$ ', the null point is obtained at a distance $30 cm$ from the left side as shown at point $D$. If $R$ is $5.6 k \Omega$, then the value of unknown resistance ' $S$ ' will be $\Omega .$View Solution
