20) what is a magnetic field? 21) in which direction do magnetic field lines always point? 22) sketch a diagram showing how a plotting compass points around a 23) name two magnetic poles that will: a) attract each other b) repel each other. 24) explain why you can use a compass to navigate. 25) what's an electromagnet? 26) list two ways to increase the strength of an electromagnet. 27) the wire in a simple motor feels a force when a current flows through it. why is this? i need answers to check mine

The chemical effect of the endocrine system is longer lasting than the chemical effect of the nervous system. select the best answer from the choices provided t f

If frequency goes up, what happens to wavelength? does it get shorter or longer?

The two metal spheres in the figure are connected by a metal wire with w switch in the middle. initially the switch is open. sphere 1, with the larger radius, i'd given a positive charge. sphere 2, with the smaller radius, is neutral. then the switch is closed. afterward, sphere 1 has charge q1, is at potential v1 and the electric field strength at its surface is e1. the values for sphere 2 are q2, v2, and e2. a. is v1 < ,> , or = to v2? explain. b. is q2 < , > , or = explain? c. is e1 < ,> ,or = to e2? explain?