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Dual Nature Of Radiation And Matter

Question
CBSEENPH12047807

The kinetic energy of an electron, which is accelerated in the potential difference of 100 V, is

  • 1.6 × 10-17 J

  • 1.6 × 10-14 J

  • 1.6 × 10-10 J

  • 1.6 × 10-8 J

Solution

A.

1.6 × 10-17 J

The energy transferred to electrons is e V joules. So each electron gains kinetic energy equal to the amount of energy transferred from the electrical supply. The electron starts from rest ( near enough ) so the Kinetic energy gained is given by 1 / 2 mv2 where m is the mass of electron and v is speed.

KE = e V

    = 1.6 × 10-19 × 100

KE = 1.6 × 10-17 J