A.Used in USA and Canada
B.Large area under first, they can’t adopt other method
C.Sometime metallic rod is fixed in centre
D.Measured after 5 or 10 years
E.All of the above
A.Used in USA and Canada
B.Large area under first, they can’t adopt other method
C.Sometime metallic rod is fixed in centre
D.Measured after 5 or 10 years
E.All of the above