Answer:
The number is 

Step-by-step explanation:
From then question we are told that 
 The current carried is 

 The speed is 

 The circumference is 

Mathematically current is expressed as 
 
 where Q is the quantity of charge passing through a conductor and t is the time in seconds 
 The time t can be mathematically represented as 
 

Substituting this into the equation fro current 
 

 Now making the quantity of charge the subject of the formula 
 

Generally the number of proton in the beam is mathematically represented as 
 

Where n is the charge on one proton with a value of 

Now substituting for q in the equation for N
 

Substituting values 
 

 
