Need help please, not sure what I did wrong. In the figure, an electron with an
ID: 2279466 • Letter: N
Question
Need help please, not sure what I did wrong.
In the figure, an electron with an initial kinetic energy of 3.80 keV enters region 1 at time t = 0. That region contains a uniform magnetic field directed into the page, with magnitude 0.00830 T. The electron goes through a half-circle and then exits region 1, headed toward region 2 across a gap of 25.0 cm. There is an electric potential difference Al/ = 2100 V across the gap, with a polarity such that the electron's speed increases uniformly as it traverses the gap. Region 2 contains a uniform magnetic field directed out of the page, with magnitude 0.0152 T. The electron goes through a half-circle and then leaves region 2. At what time t does it leave?Explanation / Answer
V = 3.656*10^7 m/s
B*e*V = m*V*V/R => R = m*V/eB = 25 mm
t = 2pi*R/V = 4.3 ns
For gap,
S = u*t + 0.5*t*t*a ; a = e*2100/m = 3.694*10^14 m/s2
putting s, a and u, calculate t.
0.25 = t*3.656*10^7 + 0.5*t*t*3.694*10^14
time = 6.167 ns
Velocity at region 2..
v = u+ at = 3.884*10^7
time = 2pi*R/v = 2*pi*m/2B = 2.349 ns
Total time = 1.282*10^8 sec