Question

#12

uniform magnetic field of strength (2T). Find the magnitude of the force on the wire. Answer in units of N 008 (part 1 of 2) 10.0 points A 10 A current is directed along the post- tive s-axis and perpendicularly to a uniform magnetic field. The conductor experiences a magnetic force per unit length of 0.19 N/min the negative y direction Calculate the magnitude of the magnetic field in the region through which the current 012 10.0 points Consider two straight wires each carrying cur rent I, as shown. 1. Upwards 2. Downwards 3. It is impossible for the net force on the middle wire to be zero 4. There should be no current in the third wire. What is the direction of the magnetic field at point R (midpoint between the two wires) Cised by the two current carrying wires? 1. To the 2. Towards the bottom wire 3. To the right 4. Into the page 5. There is no magnetic field 6. Out of the page 7. Towards the top wire 014 10.0 points Two long parallel wires are separated by 8.9 cm. One of the wires carries a current of 50 A and the other carries a current of SIA Determine the magnitude of the magnetic force on a 5.7 m length of the wire carrying the greater current Answer in units of IN 013 10.0 points Consider three evenly spaced parallel wires arranged in a row is shown. th ? The first two wires have equal amounts of current flowing in opposite directions as shown above. What direction should the cur- rent in the third wire flow in order for the net force on the middle wire to be zero?

Answer 1

12. Using Ampere's law around a loop containing the point(R) on it's circumference and center on the axis of the wire and a radius equal to the perpendicular distance from R to the axis of the wire, we got

   $B=\frac{\mu _{0}I}{2\pi r}$ [where r is the perpendicular distance from point R to the axis of the wire]

And it will point into the page if the point R is on the right of the wire and vice versa(it will point out of the page if point R is on left of the wire) .

Now, as R is midpoint between the two wires, the magnitude of magnetic field at R due to the two wires will be same, but the direction will be opposite to each other. (For the left wire it will point into the page and for right wire it will point out of the page).

So eventually they will cancel each other. So the correct option will be -

  5. There will be no magnetic field.

Here only #12 is asked to do. So I did okly #12, not #13 or #14.