Question
The purpose of cathode in cathode ray tube is ______:

Answer

  1. To emit the electrons
Explanation:
The heated filament transfers its heat to the cathode the cathode coated by oxides of Barium or Strantium emit electrons on heating.

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

Similar questions

The $e.m.f.$ in a thermoelectric circuit with one junction at $0^{\circ} \mathrm{C}$ and the other at $t^{\circ} \mathrm{C}$ is given by $\mathrm{E}=\mathrm{At}-\mathrm{Bt}^2.$ The neutral temperature is then
The angle of dip is the angle(a) Between the vertical component of earth's magnetic field and magnetic meridian(b) Between the vertical component of earth's magnetic field and geographical meridian(c) Between the earth's magnetic field direction and horizontal direction(d) Between the magnetic meridian and the geographical meridian
 
 
 
 
A coil of wire of a certain radius has $600$ turns and a self inductance of $108\ mH$. The self inductance of a $2^{nd}$ similar coil of $500$ turns will be
In the circuit element given here, if the potential at point $B, V_B = 0,$ then the potentials of $A$ and $D$ are given as
A free neutron decays into a proton, an electron and(a) A neutrino(b) An antineutrino(c) An alpha particle(d) A beta particle
       
The magnitude of the vector product of two vectors $\big|\overrightarrow{\text{A}}\big|$ and $\big|\overrightarrow{\text{B}}\big|$ may be:
  1. Greater than AB.
  2. Equal to AB.
  3. Less than AB.
  4. Equal to zero.
A molecule with a dipole moment p is placed in an electric field of strength E. Initially the dipole is aligned parallel to the field. If the dipole is to be rotated to be anti-parallel to the field, the work required to be done by an external agency is(a) – 2pE(b) – pE(c) pE       (d) 2pE
       
The charge on proton is:
The energy of electron in the nth orbit of hydrogen atom is expressed as $\mathrm{E}_{\mathrm{n}}=-\frac{13.6}{\mathrm{n}^2} \mathrm{eV}$. The shortest and longest wavelength of Lyman series will be
Finger prints are observed by the use of(a) Telescope (b) Microscope (c) Gallilean telescope (d)  Concave lens