Answer :
It's in the negative direction since acceleration is in positive direction.
How we do it?
The magnetic field must first be in the opposite direction from acceleration, since acceleration occurs in the positive x-direction.
We know that the magnitude of the Lorentz force F is; F = q v B sinθ
So, B = F/(qvsinθ)
F = ma.
Speed(v) = 1.25 x10^(7) m/s
Acceleration (a) = 2.45 x10^(13) m/s^(2)
Mass of proton = 1.673 × 10^(-27) kilograms
q(elementary charge of proton) = 1.602×10^(−19)
Since right hand thumb rule, θ= 90°
So, B = [1.673 × 10^(-27) x 2.45 x10^(13)] / [ {1.602×10^(−19)} x {1.00 x10^(7)} x sin 90]
So ,B = 2.55 x 10^(-2) T.
It's in the negative direction since acceleration is in positive direction.
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