Gwith what tension must a rope with length 2.50 m and mass 0.120 kg be stretched for transverse waves of frequency 40.0 hz to have a wavelength of 0.750 m?

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.