Rate of effusion of gas
                
              
              
                1
              
            
            
              
                
                  Rate of effusion of gas
                
              
              
                2
              
            
          
        
        =
        
          
            
              
                M
                
                  2
                
              
              
                M
                
                  1
                
              
            
          
        
      
    
    {\displaystyle {{\mbox{Rate of effusion of gas}}_{1} \over {\mbox{Rate of effusion of gas}}_{2}}={\sqrt {M_{2} \over M_{1}}}}
  where 
  
    
      
        
          M
          
            1
          
        
      
    
    {\displaystyle M_{1}}
   and 
  
    
      
        
          M
          
            2
          
        
      
    
    {\displaystyle M_{2}}
   represent the molar masses of the gases.
{\displaystyle \Phi _{N}={\frac {\Delta PAN_{A}}{\sqrt {2\pi MRT}}}.}