Which of these statements is true?
a.
some molecules may contain no atoms.
b.
some elements found in nature exist as molecules.
c.
some compounds include only one type of element.
d.
some atoms are made of two or more different elements.

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.