consider a small portion of the arc
now let the small portion be dl
so charge dq= λdl
but dl = a d@ where @ is teh angle subtended by it at the cnetre
thus dq=λ a d@
dE=K dq/a^2 sin@ bcos the cos@ components gets cancelled due to symmetry
dE = K λa d@ / a^2 sin@
integrating both sides with limits 0 to E for E and 0 to pie for right hand side
E =K λ/a *[cos pie - cos 0]
= 2K λ / a
consider a small portion of the arc
now let the small portion be dl
so charge dq= λdl
but dl = a d@ where @ is teh angle subtended by it at the cnetre
thus dq=λ a d@
dE=K dq/a^2 sin@ bcos the cos@ components gets cancelled due to symmetry
dE = K λa d@ / a^2 sin@
integrating both sides with limits 0 to E for E and 0 to pie for right hand side
E =K λ/a *[cos pie - cos 0]
= 2K λ / a