The discussion centers on calculating the number of electrons required to transfer 1 Joule of energy to a screen, given the kinetic energy of a single electron moving at 5.0 * 10^5 m/s. The correct kinetic energy of one electron is established as 1.14 * 10^-19 J. To transfer 1 J of energy, the accurate calculation reveals that 8.8 * 10^18 electrons are needed, correcting the initial miscalculation of 1.14 * 10^19 electrons. The error stemmed from a misunderstanding of exponent manipulation and the mantissa in scientific notation.
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An elecetron has a mass of 9.11 * 10^-31 kg. If it moves across a television picture tube at a speed of 5.0 * 10^5 m/s. Calculate:
a) it's kinetic energy
b)how many such electrons would transfer 1 J of energy to the screen.
sakonpure6 said:My answer to a) is 1.14 * 10^-19 J, which is correct.
My answer to b) is 1.14 * 10^19, which is not correct. The correct answer is 8.8 * 10^18. How did they get that? because if 1 electron has 1.14 * 10^-19 J then won't we need 1.14 * 10^19 electrons for 1 J ?