In an electron gun the control grid is given a negative potential… - Vidyadip

Question

In an electron gun the control grid is given a negative potential relative to cathode in order to (a) Decelerate electrons(b) Repel electrons and thus to control the number of electrons passing through it(c) To select electrons of same velocity and to converge them along the axis(d) To decrease the kinetic energy of electrons

✓

Answer

(b) Repel electrons and thus to control the number of electrons passing through it

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from Electron, Photon, Photoelectric Effect and X-Rays→Electron, Photon, Photoelectric Effect and X-Rays — all question types→Physics STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

The value of scattering angle of alpha particle for minimum value of impact parameter is-

Choose the correct answer from alternatives given.
If $\overrightarrow{\text{E}}$ and $\overrightarrow{\text{B}}$ represent electric and magnetic field vectors of an electromagnetic wave, the direction of propagation of the wave is along.

Assertion : Photoelectric effect demonstrates the wave nature of light.
Reason : The number of photoelectrons is proportional to the frequency of light.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

A metallic resistor is connected across a battery. If the number of collisions of the free electrons with the lattice is somehow decreased in the resistor $($for example, by cooling it$)$, the current will:

An electron $\left(\right.$ charge $\left.=1.6 \times 10^{-19} \mathrm{C}\right)$ is accelerated through a potential of $100,000\ V.$ The energy acquired by the electron is

A double star is a system of two stars rotating about their centre of mass only under their mutual gravitational attraction. Let the star have mass $m$ and $2m$ and their separation be $l.$ Their time period of rotation about their centre of mass will be proportional to

The distance of closest approach of an alpha particle is $d$ when it moves with a speed $V$ towards a nucleus.
Another alpha particle is projected with higher energy such that the new distance of the closest approach is $d/2$ . What is the speed of projection of the alpha particle in this case?

A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will:

In a stationary wave,

All the particles of the medium vibrate in phase.
All the antinodes vibrate in phase.
The alternate antinodes vibrate in phase.
All the particles between consecutive nodes vibrate in phase.

In a P-type semi-conductor, germanium is dopped with(a) Gallium (b) Boron(c) Aluminium(d) All of these