| #3526 |
What is the relation between electricity and magnetism? |
Moving charges produce magnetic fields; changing magnetic fields induce electric currents |
| #3527 |
What is magnetic susceptibility? |
Degree to which a material can be magnetized |
| #3528 |
Give examples of ferromagnetic materials. |
Iron, Cobalt, Nickel |
| #3529 |
What are the magnetic properties of materials? |
Diamagnetic (weakly repelled), Paramagnetic (weakly attracted), Ferromagnetic (strongly attracted) |
| #3530 |
What is the formula for ideal transformer current ratio? |
I_s / I_p = N_p / N_s |
| #3531 |
What is the formula for ideal transformer voltage ratio? |
V_s / V_p = N_s / N_p, where N is number of turns |
| #3532 |
What is the principle of transformer operation? |
Mutual induction between primary and secondary coils |
| #3533 |
What is a transformer? |
Device to increase or decrease AC voltage using electromagnetic induction |
| #3534 |
What is the difference between AC and DC generators? |
AC generator produces alternating current; DC generator produces direct current |
| #3535 |
What is a generator? |
Device that converts mechanical energy into electrical energy using electromagnetic induction |
| #3536 |
What is Lenz’s Law? |
Induced current always flows in a direction to oppose the change in magnetic flux |
| #3537 |
What are Faraday’s laws of electromagnetic induction? |
1st: Induced EMF is proportional to rate of change of magnetic flux; 2nd: Direction of induced EMF opposes the change (Lenz’s Law) |
| #3538 |
What is electromagnetic induction? |
Production of induced EMF or current in a conductor due to change in magnetic flux |
| #3539 |
What is a solenoid? |
A coil of wire carrying current, producing a magnetic field similar to a bar magnet |
| #3540 |
What is the magnetic effect of electric current? |
Current produces a magnetic field around a conductor, basis for electromagnets and motors |
| #3541 |
What is the chemical effect of electric current? |
Electric current causes chemical reactions, as in electrolysis |
| #3542 |
What is the heating effect of electric current? |
Electric current produces heat in a conductor, as in electric heaters (Joule’s law: H = I²Rt) |
| #3543 |
What is electrical power? |
Rate at which electrical energy is consumed or generated, P = VI |
| #3544 |
How are resistances combined in parallel? |
1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + … |
| #3545 |
How are resistances combined in series? |
R_total = R₁ + R₂ + R₃ + … |
| #3546 |
What factors affect resistance? |
Material, length, cross-sectional area, and temperature of the conductor |
| #3547 |
What is resistance? |
Opposition offered by a conductor to the flow of current, measured in Ohms (Ω) |
| #3548 |
What is Ohm’s Law? |
Current through a conductor is directly proportional to the voltage and inversely proportional to resistance, V = IR |
| #3549 |
What is the SI unit of current? |
Ampere (A) |
| #3550 |
What is current? |
Rate of flow of electric charge, I = Q/t |