G You are near a long straight current-carrying wire, and you measure the magnetic field due to the current in the wire at a location a distance d from the wire. If you move to a point 2d away from the wire and measure the magnetic field due to the current in the long straight wire, how will the magnitude compare to the field d away from the wire

B_2 / B_1 = 0.5 , Half of magnetic field at distance d.

Explanation:

Given:

- A current carrying conductor produces a magnetic field = B_1  @ r = d

- A current carrying conductor produces a magnetic field = B_2  @ r = 2*d

Find:

Compare the the magnetic Field at two points r = d and r = 2*d:

Solution:

- The magnetic Field of long current carrying wires are expressed as follows:

                                      B = u_o*I / 2*pi*r

Where,

B = Magnetic Field

I = The current in the conductor

r = The radial distance from the center of the wire.

u_o = Permittivity of free space (constant)

- Now compute B_1 and B_2:

                                    B_1 =   B = u_o*I / 2*pi*d

                                    B_2 =   B = u_o*I / 4*pi*d

- Take a ratio of B_2 to B_1:

                                    B_2 / B_1 = (u_o*I / 4pi*d) * ( 2*pi*d/u_o*I)

                                    B_2 / B_1 = 0.5

- Hence, the magnetic field at distance 2d is half of the magnetic field at distance d.

answer: d. a cme increases the amount of energy in the solar wind

explanation:

coronal mass ejections, also called cmes, are large clouds of plasma and magnetic field that erupt from the sun. only when the cloud is aimed at earth will the cme hit earth and therefore cause impacts. high-speed solar wind streams come from areas on the sun known as coronal holes.

multiple