Question
If the thermionic current density is $J$ and emitter temperature is $T$ then the curve between $\frac{J}{{{T^2}}}$ and $\frac{1}{T}$ will be
✓
Answer
(c)$J = A{T^2}{e^{ - b/T}}$ ==> $\frac{J}{{{T^2}}} \propto {e^{ - b/T}}$
i.e. $\frac{J}{{{T^2}}}$ will vary exponentially with $\frac{1}{T}$, having negative slope.
i.e. $\frac{J}{{{T^2}}}$ will vary exponentially with $\frac{1}{T}$, having negative slope.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
The kinetic energy, due to translational motion, of most of the molecules of an ideal gas at absolute temperature $T$ is
→The $K_{eq.}$ values in $HCN$ addition to following aldehydes are in the order
→A potential difference of $10 \,V$ is applied across a conductor of $1000 \,\Omega$. The number of electrons flowing through the conductor in $300 \,s$ is ..........
→In an experiment to find surface tension of mercury with the help of capillary rise method the liquid column in capillary will
During an isothermal expansion, a confined ideal gas does $-150 \,J$ of work against its surroundings. This implies that
→The correct relation between the degree of freedom $f$ and the ratio of specific heat $\gamma$ is
→In an $AC$ generator, a coil with $N$ turns, all of the same area $A$ and total resistance $R$, rotates with frequency $\omega $ in a magnetic field $B$. The maximum value of $emf$ generated in the coil is
→Given below are two statements :
→Statement $I$ : When speed of liquid is zero everywhere, pressure difference at any two points depends on equation $\mathrm{P}_1-\mathrm{P}_2=\rho \mathrm{g}\left(\mathrm{h}_2-\mathrm{h}_1\right)$
Statement $II$ : In ventury tube shown $2 \mathrm{gh}=v_1^2-v_2^2$
In the light of the above statements, choose the most appropriate answer from the options given below.
A body moves a distance of $10 \,m$ along a straight line under the action of a force of $5 \,N$. If the work done is $25\, joules$, the angle which the force makes with the direction of motion of the body is.....$^o$
→As shown in the figure an inductor of inductance $200\, mH$ is connected to an $AC$ source of emf $220 \,V$ and frequency $50 \,Hz$. The instantaneous voltage of the source is $0\, V$ when the peak value of current is $\frac{\sqrt{a}}{\pi} A$. The value of a is..........
→