Protons move in a circle of radius 4.40 cm in a 0.580 T magnetic field.?

Question

What value of electric field could make their paths straight? V/m?

Answer 1

Ok, I have this idea :

If the protons move in a circle, so the radial force must be equal to the electromagnetic force :

q*v*B = M*v^2 / R

charge of the proton : 1.6*10^-19

mass of the proton : 1840*9.1*10^-31 kg

R = m*v / q*B

4.40*10^-2 = 1840*9.1*10^-31*V / 1.6*10^-19*0.58

V = 2.44*10^6 m/s

Now, the electromagnetic force now will be equal to the electric force made by the electric field, so the paths will be straight :

1.6*10^-19*2.44*10^6*0.58 = E*1.6*10^-19

E = 1.41*10^6 (V / m)

Hope that might help you