Positive point charge `q=+8.00muC and q'=+3.00muC` are moving relative to an observer in Fig. The distance d is 0.120m. When the two charges are at the locations shown in the figure, what are the magnitude and direction of the net magnetic field they produce at point P? `(Take v=4.50xx10^6ms^-1 and v'=9.00xx10^6ms^1)`

Options

A. `4.38xx10^-4T`, into the page
B. `4.38xx10^-4T`, out of the page
C. `2.16xx10^-4T`, into the page
D. `2.16xx10^-4T`, out of the page

Answer

A

Explanation

(a) `B_("total")=B+B'=(mu_0)/(4pi)((qv)/(d^2)+(q'v')/(d^2))`
`B=(mu_0)/(4pi)(((8.0xx10^-6C)(4.5xx10^6ms^-1))/((0.120m)^2)`
`+((3.0xx10^-6C)(9.0xx10^6ms^-1))/((0.120ms)^2))`
`B=4.38xx10^-4T`, into the page.