GS One‑Liners
high‑yield facts · smart revision
5107
facts
5107
results
Latest facts first
| # | Question & Answer |
|---|---|
| 4076 |
What is the relation between electricity and magnetism?
-
Moving charges produce magnetic fields; changing magnetic fields induce electric currents
|
| 4077 |
What is magnetic susceptibility?
-
Degree to which a material can be magnetized
|
| 4078 |
Give examples of ferromagnetic materials.
-
Iron, Cobalt, Nickel
|
| 4079 |
What are the magnetic properties of materials?
-
Diamagnetic (weakly repelled), Paramagnetic (weakly attracted), Ferromagnetic (strongly attracted)
|
| 4080 |
What is the formula for ideal transformer current ratio?
-
I_s / I_p = N_p / N_s
|
| 4081 |
What is the formula for ideal transformer voltage ratio?
-
V_s / V_p = N_s / N_p, where N is number of turns
|
| 4082 |
What is the principle of transformer operation?
-
Mutual induction between primary and secondary coils
|
| 4083 |
What is a transformer?
-
Device to increase or decrease AC voltage using electromagnetic induction
|
| 4084 |
What is the difference between AC and DC generators?
-
AC generator produces alternating current; DC generator produces direct current
|
| 4085 |
What is a generator?
-
Device that converts mechanical energy into electrical energy using electromagnetic induction
|
| 4086 |
What is Lenz’s Law?
-
Induced current always flows in a direction to oppose the change in magnetic flux
|
| 4087 |
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)
|
| 4088 |
What is electromagnetic induction?
-
Production of induced EMF or current in a conductor due to change in magnetic flux
|
| 4089 |
What is a solenoid?
-
A coil of wire carrying current, producing a magnetic field similar to a bar magnet
|
| 4090 |
What is the magnetic effect of electric current?
-
Current produces a magnetic field around a conductor, basis for electromagnets and motors
|
| 4091 |
What is the chemical effect of electric current?
-
Electric current causes chemical reactions, as in electrolysis
|
| 4092 |
What is the heating effect of electric current?
-
Electric current produces heat in a conductor, as in electric heaters (Joule’s law: H = I²Rt)
|
| 4093 |
What is electrical power?
-
Rate at which electrical energy is consumed or generated, P = VI
|
| 4094 |
How are resistances combined in parallel?
-
1/R_total = 1/R₁ + 1/R₂ + 1/R₃ + …
|
| 4095 |
How are resistances combined in series?
-
R_total = R₁ + R₂ + R₃ + …
|
| 4096 |
What factors affect resistance?
-
Material, length, cross-sectional area, and temperature of the conductor
|
| 4097 |
What is resistance?
-
Opposition offered by a conductor to the flow of current, measured in Ohms (Ω)
|
| 4098 |
What is Ohm’s Law?
-
Current through a conductor is directly proportional to the voltage and inversely proportional to resistance, V = IR
|
| 4099 |
What is the SI unit of current?
-
Ampere (A)
|
| 4100 |
What is current?
-
Rate of flow of electric charge, I = Q/t
|