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One electron collides elastically with a second electron initially at rest. After the collision, the radii of their trajectories are 1.00 cm and 2.40 cm. The trajectories are perpendicular to a uniform magnetic field of magnitude 0.0540 T. Determine the energy (in keV) of the incident electron.

Respuesta :

Answer:

KE = 160.41 keV

Explanation:

given data

radii = 1.00 cm

radii  = 2.40 cm

uniform magnetic field of magnitude =  0.0540 T

to find out

energy (in keV) of the incident electron

solution

first we find the velocity of charge with radii 1 cm then 2.40 cm by given formula

R = [tex]\frac{mv}{qB}[/tex]   ......................1

put here value

1 × [tex]10^{-2}[/tex] = [tex]\frac{9.1*10^{-31}*v}{1.6*10^{-19}*0.052}[/tex]

solve we get

v = 91428571 m/s

and with radii 2.40 from equation 1

R = [tex]\frac{mv}{qB}[/tex]

2.4 × [tex]10^{-2}[/tex] = [tex]\frac{9.1*10^{-31}*v1}{1.6*10^{-19}*0.052}[/tex]

solve we get

v1 = 219428570 m/s

so

now we calculate energy of incident electron

KE = 0.5 m (v² + v1² )

KE = 0.5 ×9.1×[tex]10^{-31}[/tex]× (91428571² + 219428570² )

KE = 2.57 × [tex]10^{-14}[/tex] J

KE = 2.57 × [tex]10^{-14}[/tex] J × 6.242 × [tex]10^{15}[/tex]

KE = 160.41 keV