Answer:
The magnetic field strength is required

Step-by-step explanation:
Given that,
Speed of proton

Mass of proton

Charge
When a proton moves horizontally, at a right angle to a magnetic field .
Then, the gravitational force balances the magnetic field


Here,

Where, B = magnetic field
q = charge
v = speed
Put the value into the formula


Hence, The magnetic field strength is required
