Question

The concept of thermionic emission is the basis of modern X-ray tubes, which are the workhorse of a medical X‑ray image. In this process, a filament (a piece of metal in a vacuum) is heated by the application of electrical current. The heat (energy) is transferred to the 'free' electrons of the metal, which allows some electrons to escape from the surface. After a short period of operation, the filament has lost enough electrons to give it an overall charge of 1.250×10−61.250×10−6 C.

How many electrons, ?ene, has the filament lost? If the filament is 2.452.45 g of tungsten, what fraction of electrons, efef, does this represent? (HINT: The atomic number of tungsten is 74.074.0, the atomic weight is 183.8183.8 g/mol, and Avogadro's constant equals 6.02×10236.02×1023 atoms/mol.)

Two particles, one with charge −2.93 μC−2.93 μC and one with charge 5.23 μC,5.23 μC, are 4.34 cm4.34 cm apart. What is the magnitude of the force that one particle exerts on the other?

force:

NN

Two new particles, which have an identical positive charge ?3,q3, are placed the same 4.34 cm4.34 cm apart, and the force between them is measured to be the same as that between the original particles. What is ?3?q3?

Answer 1

19 le - Therefore initial tongent modules for the matesoal is [; 3x1041 According to the condition given in Question we have charge of 1 Gectron = 106x1092c Total charge = 1,25x106c No. of Electrons = (1125x106) (1.6x10-19) No.of Electrons lost = 1.98x10 Elections Atomic mass of tungsten = 183.8 Moss

183.89 m = 6.022 x 163 21459 - 61022x1023 183.8*2.45 Ne 8.02 x 1021 Total Electrons - Atomic number in Total Electrons = 74.8 x 8.02x 1021 Total Elections - 5.93 x 1023 fraction of Liectoons » 1.28 x 10' - 5.93×10 23 fraction Electrons = 0.215x 10" = 2.15 x1012 -2,43HC 5.2 Mc 1. F = KQ, Q2 -6 F- 9x 10 x 243 X 10 X 5123 XD 20.0434) Fc 137.91 x 103 10883 x 103 F = 73.230 force of attraction

Electóc force between two charged Particles q and q 2 F = kq 9 2 dr here q = 92 = 93 So F = kq 319 3 de 83 - 0V 103 = 1.23*10*c]