Explanation:
If you wrap some of the wire around the nail in one direction and some of the wire in the other direction, the magnetic fields from the different sections fight each other and cancel out, reducing the strength of your magnet
Answer:
B. most electrical devices in a house are on parallel circuits.
Explanation:
Household wiring is a mostly a series of parallel circuits. Otherwise, if you were to turn your oven (or television, or your computer, or any other appliance off, the rest of your home's electrical system will cease to operate.
Therefore, they are in parallel circuits.
Answer:
61.85 ohm
Explanation:
L = 12 m H = 12 x 10^-3 H, C = 15 x 10^-6 F, Vrms = 110 V, R = 45 ohm
Let ω0 be the resonant frequency.
ω0 = 2357 rad/s
ω = 2 x 2357 = 4714 rad/s
XL = ω L = 4714 x 12 x 10^-3 = 56.57 ohm
Xc = 1 / ω C = 1 / (4714 x 15 x 10^-6) = 14.14 ohm
Impedance, Z = 
Z = \sqrt{45^{2}+\left ( 56.57-14.14 )^{2}} = 61.85 ohm
Thus, the impedance at double the resonant frequency is 61.85 ohm.
D.It draws objects together in proportion to their mass
Answer:
The poles of the magnetic field generated around the armature are attracted to the opposite poles of the permanent magnet. As the opposite poles align, the commutator reverses the current direction so like poles are aligned and the armature continues to spin.
Explanation:
