6.12 An electron and a proton are detected in a cosmic ray experiment, the first with kinetic energy 10 keV, and the second with 100 keV. Which is faster, the electron or the proton ? Obtain the ratio of their speeds. (electron mass = 9.11×10-31 kg, proton mass = 1.67×10–27 kg, 1 eV = 1.60 ×10–19 J).
6.12 An electron and a proton are detected in a cosmic ray experiment, the first with kinetic energy 10 keV, and the second with 100 keV. Which is faster, the electron or the proton ? Obtain the ratio of their speeds. (electron mass = 9.11×10-31 kg, proton mass = 1.67×10–27 kg, 1 eV = 1.60 ×10–19 J).
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1 Answer
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6.12 Electron mass, me = 9.11*10-31 kg
Proton mass, madhya pradesh = 1.67*10–27 kg
Electron's kinetic energy = 10 keV = 10 1.60 *10–19 J = 1.60 *10–15 J
Proton's kinetic energy = 100 keV = 100 1.60 *10–19 J = 1.60 *10–14 J
The electron kinetic energy is given by Eke = (1/2)m where is the velocity of electron
= { (2 Eke )/m} = 5.92 m/s
The velocity of proton = { (2 Pke )/m} = 4.37 m/s
The speed ratio = / = 13.5
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