Answer: 178.25*10^-6 T
Explanation: In order to solve this problem we have to take into account the equilibrium between the electric and magnetic forces in the electron, so it is given by:
Fm=evB
Fe=eE so
evB=eE the we have
v=E/B
Firsly we calculate the velocity of the electron before to get the parallel plates at 100V
eΔV=1/2*m*v^2 then
v=(2*eΔV/m)^1/2
v=(2*1.6*10^-19*3.1*10^3/9.1*10^-31)^1/2=33 *10^6 m/s
Then we can calculate B
B=E/v E.d=V where d is the separation between the plates and V is equal a 100V
B=V/(d*v)=100/(17*10^-3*33 *10^6)=178.25*10^-6 T
A wave with a period of 1⁄3 second has a frequency of D. 3 Hz. To
calculate this we will use the formula that represents the correlation
between a frequency (f) and a time period (T): T = 1/f. Or: f = 1/T. The
unit for the time period is second "s" while the unit for frequency is
Hertz "Hz" (=1/s). We know that T = 1/3 s. That means that f = 1/(1/3s) =
3 1/s = 3 Hz.