MCQ
In a diode valve the cathode temperature must be ($\phi$ = work function)
- AHigh and $\phi$should be high
- ✓High and $\phi$ should be low
- CLow and $\phi$ should be high
- DLow and $\phi$should be high
✓
Answer
Correct option: B.
High and $\phi$ should be low
b
In a diode value the cathode temperature must be high and $\phi$ should be low.
In a diode value the cathode temperature must be high and $\phi$ should be low.
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
In a triode valve
Two coils of self inductances $2\, mH$ and $8\, mH$ Hare placed so close together that the effective flux in one coil is completely linked with the other. The mutual inductance between these coils is......$mH$
→The first excited state of hydrogen atom is $10.2 \,eV$ above its ground state. The temperature is needed to excite hydrogen atoms to first excited level, is
→Column $I$ Contains a list of processes involving expansion of an ideal gas. Match this with Column $II$ describing the thermodynamic change during this process. Indicate your answer by darkening the appropriate bubbles of the $4 \times 4$ matrix given in the $ORS$.
→| Column $I$ | Column $II$ |
| $(A)$ An insulated container has two chambers separated by a valve. Chamber $I$ contains an ideal gas and the Chamber $II$ has vacuum. The valve is opened. | $(p)$ The temperature of the gas decreases |
| $(B)$ An ideal monoatomic gas expands to twice its original volume such that its pressure $\mathrm{P} \propto \frac{1}{\mathrm{~V}^2}$, where $\mathrm{V}$ is the volume of the gas | $(q)$ The temperature of the gas increases or remains constant |
| $(C)$ An ideal monoatomic gas expands to twice its original volume such that its pressure $\mathrm{P} \propto \frac{1}{\mathrm{~V}^{4 / 3}}$, where $\mathrm{V}$ is its volume | $(r)$ The gas loses heat |
| $(D)$ An ideal monoatomic gas expands such that its pressure $\mathrm{P}$ and volume $\mathrm{V}$ follows the behaviour shown in the graph $Image$ | $(s)$ The gas gains heat |
A long stiff uniform wire is suspended from one end. The time period of oscillations of the wire is $T$. If the wire is now bent into a circle and suspended from a knife edge so that it can oscillate freely in the plane of the ring, its time period will be
→A body of $0.5 \,kg$ moves along the positive $X$-axis under the influence of a varying force $F$ (in newton) as shown below.If the speed of the object at $x=4 \;m$ is $3.16 \,ms ^{-1}$, then its speed at $x=8 \,m$ is ................. $\,ms ^{-1}$
→A plane polarised light passed through successive polarisers which are rotated by $30^{\circ}$ with respect to each other in the clockwise direction. Neglecting absorption by the polarisers and given that the first polariser's axis is parallel to the plane of polarisation of the incident light, the intensity of light at the exit of the fifth polariser is closest to
→The potential energy of a particle executing S.H.M. is $ 2.5\, J$, when its displacement is half of amplitude. The total energy of the particle be .... $J$
→In a meter bridge the point $D$ is neutral point as shown in the figure.
→A nucleus ruptures into two nuclear parts which have their velocity ratio equal to $2 : 1$. What will be the ratio of their nuclear size (nuclear radius)
→