neeraj is right and

electric potential is not defined in case of a line charge and the reason gvn by neeraj is perfect

 

hey yaar its rite tha ans is 40 km/s

again n again i made a mistake insubst.

my logic is correct

if u still don understand i can xplain it

put z= x+iy and z bar =x-iy and solve

get an eqn of gen form of circle

x^2+y^2+2gx+2fy+c=0

r=sqrt(g^2+f^2-c)

ans is sqrt(20) units

wat do u mean i have considered the wire to be finite?

in the formula basically the angles

1 and

2are the angles subtended by the endpts of the wire on the pt where field is reqd. here as one end is infin. and another finite. theta 1 is 90 and the other angles  is 90- theta /.

if u still think ma soln is wrong nudge me

 

no dude its like u r bendin a single infinitely long wire at a point

itll give 2 divergent wires starting frm a point

i don think the question is clear

try to be more clear sweetgal

awadesh clarify ur question

is it in a triangle then the ans is  

 

ans is 100/3 in prop units

well dude i got ma mistake

heres da right soln

let dist of the pt be d from both da lines

B at the reqd pt say O ,

i hav written down B due 2 1 wire (its not clear in ma pic)

is da ans 4 magn field correct.

i feel i made a small mistake

well as for ur second question i'd say its a consequence of ampere's circuital law

consider a circular loop wthin the tube passin thru the point were field is reqd.

 

well sorry sudakar i took semi minor axis to be2*10^12. sorry

any way repeat the same steps as i have done wid da correction

but still i don think da ans is 40000.

im gettin 23157 m/s

 

areal velocity is dA/dT= L/2m is a standard property, whose proof will be gvn in any standard text