Question

the kinetic energy of an electron in tube is 25000eV. The percentage increase in electron rest mass is
​

Answer 1

to find the increase in electron rest mass at

KE=25eV, use

KE=1/2mV^2, Find

The Formula M=m\{1-V^2\C^2}^1\2

Answer 2

Answer:

percentage increase in mass -48.92%  

Explanation:

Now the kinetic energy of accelerated electron is given by,

$K.E=mc^{2} -m_{0} c^{2}$

where m= relativistic mass of electron , $m_{0}$= rest mass of electron and c= velocity of light

so,$\frac{K.E}{m_{0} c^{2} } =\frac{mc^{2}- m_{0} c^{2}}{m_{0} c^{2}}$

$=\frac{m-m_{0} }{m_{0} }$

Thus, percentage increase in mass $=\frac{m-m_{0} }{m_{0} }$*100

                                                            =$\frac{K.E}{m_{0} c^{2} }$*100

                                                             =$\frac{ 25000eV}{0.511*10^{6} }*100 =48.92%$%

where m0c2=0.511MeV

     ∴ percentage increase in mass -48.92%

#SPJ3