In a lightning bolt, a large amount of charge flows during a time of 2.2 10-3 s. Assume that the bolt can be treated as a long, straight line of current. At a perpendicular distance of 28 m from the bolt, a magnetic field of 7.3 10-5 T is measured. How much charge has flowed during the lightning bolt? Ignore the earth's magnetic field.

Question

In a lightning bolt, a large amount of charge flows during a time of 2.2  10-3 s. Assume that the bolt can be treated as a long, straight line of current. At a perpendicular distance of 28 m from the bolt, a magnetic field of 7.3  10-5 T is measured. How much charge has flowed during the lightning bolt? Ignore the earth's magnetic field.

I thought I had to solve for I using B = mu*I/2pi*r and then figure out the current but I am stuck now.  Please help

Danny · Accepted Answer

B=U•I/2π•r I=B•2π•r/U Once you solve for I then we use the I=Q/T formula Q=I•T

Elena · Answer

B= μ₀•I/2π•d= μ₀•q•t/2π•d q=2π•d•B/ μ₀•t= =2π•28•7.3•10⁻⁵/4π•10⁻⁷•2.2•10⁻³=4.64•10⁶ C

Anonymous · Answer

thanks!