Show all work The figure shows a velocity selector that can be used to measure t
ID: 1435249 • Letter: S
Question
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The figure shows a velocity selector that can be used to measure the speed of a charged particle. A beam of particles is directed a along the axis of the instrument. A parallel plate capacitor sets up an electric field E, which is oriented perpendicular to a uniform magnetic field B. If the plates are separated by 5.0 mm and the value of the magnetic field is 0.60 T, what voltage between the plates will allow particles of speed 5.0 times 10^5 m/s to pass straight through without deflection?Explanation / Answer
from fleming left hand rule
the magnetic force Fb = q*v*B acts upwards
the electric force Fe = E*q is down wards
for the charge to pass straight
Fe = Fb
E*q = q*v*B
E = v*B
E = 5*10^5*0.6 = 3*10^5 V/m
potential difference = dV = E*d = 3*10^5*5*10^-3 = 1500 V <<<<----answer