Electrons, Waves And Photons Definitions

Question 0

Coulomb

Answer 0

Unit C, symbol is Q, The quantity of charged transferred in one second by a current of one ampere

Question 1

Current

Answer 1

I, measured in amps, the amount of electrical charge transferred per unit time (rate of flow of electrical charge)

Question 2

Kirchhoff’s first law

Answer 2

The sum of the currents entering any junction is always equal to the sum of the currents leaving the junction (due to conservation of charge)

Question 3

Mean drift velocity

Answer 3

In ms^1, I=vAne, the average velocity that a particle such as an electron attains due to an electric field

Question 4

Potential difference

Answer 4

V, The electrical energy transferred per unit charge when electrical energy is converted into another form of energy

Question 5

One volt

Answer 5

The potential difference across a conductor when a current of one amp dissipates one watt of power

Question 6

Electromotive force

Answer 6

V, the electrical energy transferred per unit charge when one other form of energy is converted into electrical energy

Question 7

Resistance

Answer 7

R, omega, the opposition of a circuit to the flow of electric current

Question 8

One ohm

Answer 8

The resistance between two points when a potential difference between them of 1 volt produces a current of 1 amp

Question 9

Ohm’s law

Answer 9

The current in a resistive circuit is directly proportional to its applied voltage and indirectly proportional to its resistance V=IR

Question 10

Resistivity

Answer 10

Ohm metres omegam, a measure of how strongly a material opposes the flow of electric current

Question 11

Kirchhoff’s second law

Answer 11

In any closed loop in a circuit, the sum of the emfs is equal to the sum of the pds

Question 12

Terminal potential difference

Answer 12

In v, the potential difference across the terminals of a power supply V=E-IR

Question 13

Displacement

Answer 13

In metres, the distance moved by an oscillation from its mean (or rest) position

Question 14

Amplitude

Answer 14

In metres, the maximum displacement of an oscillation (always positive)

Question 15

Wavelength

Answer 15

Lambda in metres, the smallest distance between two points of a wave, that have the same pattern of oscillation

Question 16

Frequency

Answer 16

In Hz, the number of oscillations per unit time at any point

Question 17

Period

Answer 17

T in seconds, the time taken for one complete oscillation to take place

Question 18

Phase difference

Answer 18

The angle in radians between two oscillations

Question 19

Coherence

Answer 19

Two waves with a constant phase difference

Question 20

Nodes

Answer 20

Points in a stationary wave at which there is no displacement of particles at any time

Question 21

Antinode

Answer 21

The displacement of the particles in a stationary wave varies by the maximum amount

Question 22

Fundamental frequency

Answer 22

The lowest frequency in a harmonic series where a stationary wave forms

Question 23

Stationary (or standing) wave

Answer 23

A wave formed by the interference of two waves travelling in opposite directions

Question 24

Electronvolt

Answer 24

eV the amount of energy gained by an electron when it accelerates through an electric potential difference of one volt

Question 25

Threshold frequency

Answer 25

The lowest frequency of radiation that will result in the emission of electrons from a particular metal surface (usually UV light)