Physics definitions Flashcards Preview

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Flashcards in Physics definitions Deck (39):
1

photon

-a very small quanta of discrete light energy
- can be an electromagnetic wave or particle

2

Absorption spectrum

- a coloured background with black lines

3

Emission spectrum

a black background with coloured lines

4

a moment

the perpendicular distance to the pivot times the force
- forces up equal forces down
- anticlockwise moments equal clockwise moments

5

Equilibrium

an object is in equilibrium when the resultant forces acting on a particle is zero

6

Couples

a pair of forces equal in magnitude and opposite in direction

7

Centre of mass

the point at which your mass acts through

8

Difference between centre of mass and centre of gravity

the gravitational field is not uniform

9

How to improve centre of mass

lower centre of mass
widen base of the object

10

kinetic energy

energy associated with anything that is moving

11

elastic collisions

kinetic energy and momentum is conserved
small scale

12

inelastic collisions

momentum is conserved
large scale

13

Impulse

the rate of change of momentum

14

current

the flow of charge per unit time

15

voltage

how many joules of work each coulomb of charge is capable of doing

16

potential difference

-the energy transfer per unit/ from electrical to other
-charge losing energy

17

Electromotive force

the charge gaining energy

18

resistivity

the resistance a metal puts up to electric current

19

hooke's law

the force exerted on a spring is proportional to its compression, such that force divided by compression is equal to a constant k, which is measured in Nm

20

thermistor

a device that decreases its resistance as temperature increases

21

Young modulus

the modulus of elasticity

22

Brittle

something which shatters if a large stress is applied

23

Ductile

a material that can be easily shaped under tension

24

Malleable

a material that can be easily shaped under compression

25

Wavelength

the distance between two identical points on successive waves

26

amplitude

the maximum displacement of a wave

27

period

the time taken for one complete wave to pass a point

28

frequency

the number of waves that passes a fixed point per unit time

29

transverse waves

waves that have their displacement at 90 degrees to the direction of energy transfer

30

longitudinal waves

waves that have their displacement in the same direction as the energy transfer

31

phase difference

the amount a wave is in or out of sequence with another wave

32

Coherence

when two waves have a constant phase difference

33

refraction

when a wave travels from a fast medium to a slow medium or vice versa causing waves to slow down and speed up and turn

34

Interference

when two waves meet at a point, the resultant displacements the sum of individual displacements

35

path difference

-if the path difference is even and whole waves, the waves will arrive in phase
- if odd the waves will arrive out of phase

36

superconductivity

zero resistance
- occurs at low temperature
- has no resistance after a certain critical temperature

37

antiparticle

different charge
same mass, rest mass energy

38

hadrons

heavier
not fundamental
made of fundamental quarks
interacts with SNF,WNF and electrostatic if charged

39

leptons

lighter
fundamental
does not interact with the SNF
interacts with WNF and electrostatic force if charged