The evaporation of electrons from a heated surface is called

A. Radiation

B. Convection

C. Thermionic emission

D. Conduction

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  1. Calculate the flux density that will be produced by the field intensity of 2000 a. t/m for a permeability…
  2. A permanent magnet does not exert a force on
  3. A germanium atom has an atomic weight of72. How many neutrons are there?
  4. What is the diameter of an atom?
  5. If the number of valence electrons of an atom is more than 4a the substance is called
  6. Hipernik is an alloy containing __________ iron and __________ nickel.
  7. The physical motion resulting from the forces of magnetic fields is called
  8. All matters (gasa liquid and solid) are composed of
  9. The force acting on a pole of 5 Wb is 25 N. What is the intensity of the magnetic field?
  10. A substance that attracts pieces iron
  11. What is the typical saturation flux density for most magnetic materials?
  12. Why is it that the magnitude of magnetomotive force required for air gap is much greater than that required…
  13. Magnetic effects of the earth as a huge magnet with north and south poles.
  14. The evaporation of electrons from a heated surface is called
  15. The ratio of the permeability of material to the permiabiity of air or vacuum.
  16. Which of the following is a paramagnetic material?
  17. The unit of electrical energy is
  18. The amount of magnetizing force to counter balance the resid magnetic material is referred to as
  19. The process by which an emf and hence current is generated or induced in a conductor when there is a…
  20. Electrons at the outer shell are called
  21. Hysteresis refers to the ______ between flux density of the material and the magnetizing force applied.
  22. What is the unit of reluctance?
  23. The force between two magnetic poles is _______ their pole strengths.
  24. In electro-mechanical conversion devices like generators and motors the reason why a small air gap is…
  25. The magnetic field of a magnetized iron bar when strongly heated
  26. Materials that have very high permeabilities (hundreds and even thousands times of that of free space)
  27. Electric field intensity at a point due to a given charge ______ if the relative permittivity of the…
  28. When the current flowsa the magnetic field . conductor is in what direction?
  29. What is used as the dielectric material in high voltage transformers?
  30. The magnetic flux through a wire loop in a magnetic field does not d