Electric current and magnetism

Question 1

Flow of charge

Answer 1

Flow of charge persists for as long as there is a potential difference - flow of water and pumps

Question 2

Electric current

Answer 2

Flow of electric charge - rate is measured in amperes - one ampere is a rate of flow = 1 coulomb of charge per second

Question 3

Voltage sources

Answer 3

• electrical pump - generators or chemical batteries - electric circuits -charge flow through a circuit because of an applied voltage across the circuit - auto watery provides an electrical pressure of 12 volts to a circuit connected across its terminals. 12 joules of energy are supplied to each coulomb of charge that is made to flow in the circuit

Question 4

Electrical resistance

Answer 4

Resistance of a wire depends on the thickness of the wire, length of the water, its particular conductivity and its temperature - measured in ohms

Question 5

Ohms’s law

Answer 5

Current in a circuit is directly proportional to the voltage established across the circuit and its inversely proportional to the resistance of the circuit Current = voltage / resistance Amperes = volts / ohms - greater the voltage, the greater the current - the greater the resistance, the smaller the current

Question 6

Electric shook

Answer 6

Damaging effects of shock are the result of current passing through the body - an electric shock requires a difference in electric potential (voltage difference) between one part of your body and another part - ex: birds sitting on a wire

Question 7

Direct current

Answer 7

Flowing of charges in one direction

Question 8

Alternating current

Answer 8

Electrons in the circuit are moved in one direction and then in the opposite direction, alternating to and fro about relatively fixed positions

Question 9

Diode

Answer 9

Electric device that acts as a one-way valve to allow electron flow in one direction only - since AV changes its direction each half cycle, current passes through a diode only half of each period

Question 10

Electric power

Answer 10

Rate at which electric energy is converted into another form, such as mechanical energy, heat, or lighting Power = current x voltage Watts = amperes x volts

Question 11

Series circuits

Answer 11

When connected, they form a single pathway for an electron to flow between the terminals of the batter, generator, or wall socket

Question 12

Parallel circuits

Answer 12

When connected, they form branches, each of which is a separate path for the flow of electrons

Question 13

Single pathway series circuits

Answer 13

• current is resisted by the resistance of the first device, resistance of the second, and that of the third, and so on. SO the total resistance to current is the sum of the individual resistances along the path - current is numerically equal to the voltage supplied by the source divided by the total resistance of the circuit

Question 14

Total voltage of series circuits

Answer 14

• total voltage across a series circuit divides among the resistance of each individual device is = the total voltage supplied by the source - the voltage drop across each device is proportional to its resistance

Question 15

Parallel circuits cont

Answer 15

• electrical devices connected to the same two points of an electrical circuit are said to be connected in parallel - a break in any one path does not interrupt the flow fo charge in the others - each device connects the same two points of the circuit. Therefore, the voltage is the same acros each device

Question 16

Total current parallel circuits

Answer 16

• total current in the circuit divides among the parallel branches. Amount of current in each branch is inversely proportional to the resistance of the branch - total currrent in the circuit equals the sum of the currents in its parallel branches. Sum = the current in the battery or other voltage source - as number of parallel branches is increased, overall resistance of the circuit is decreased

Question 17

Magnetism

Answer 17

• magnetic poles give rise to magnetic forces - like poles repel each other; opposite poles attract

Question 18

Magnetic field

Answer 18

Region of magnetic influence around a magnetic pole or a moving charged particle - a current of charges produces a magnetic field

Question 19

Electromagnet

Answer 19

A current-carrying coil of wire - strength of an electromagnet increases by increasing the current through the coil - electromagnets that utilize superconducting coils produce extremely strong magnetic fields

Question 20

Draw parallel vs series circuits

Answer 20

Question 21

Medicine transfer

Answer 21

Question 22

Wound care

Answer 22