# current and charge Flashcards Preview

## Physics, A Level Ocr Spec a > current and charge > Flashcards

Flashcards in current and charge Deck (34)
1
Q

define displacement (waves)

A

The distance from the equilibrium positions

2
Q

define amplitude

A

max displacement

3
Q

Define wavelength

A

The minimum distance between two points in phase on adjacent waves

4
Q

Define time period of oscillation

A

the time take to for a wave to complete one oscillation

5
Q

frequency definition

A

the number of wavelengths passing a point per unit time

6
Q

wave speed

A

the distance travelled by the wave per unit time

7
Q

wave equation

A

v=f x lamda

8
Q

define phase difference

A

the difference between displacement of particles on a wave

9
Q

what is the phase difference when two particles in phase

A

10
Q

what is the phase difference when two particles in anti-phase

A

11
Q

When does reflection occur

A

reflection occurs when a wave changes direction at a boundary between two different media

12
Q

what is the law of reflection

A

angle of incidence + angle of reflection

13
Q

when does refraction occur

A

when a wave changes direction as it changes speed form one media to another

14
Q

If water is shallower the speed of the waves are ____.

A

slower

15
Q

What is diffraction?

A

when waves pass through a gap or round an obstacle and spread out

16
Q

what is polarised?

A

When a wave’s vibration is confined to one plane of oscillation

17
Q

Intensity=

A

Power/Area

18
Q

You can polarised electromagnetic waves using polarisers

A

This means only waves with a certain orientation can pass through

19
Q

The refractive index

A

speed of light in vacuum/ speed or light in a material

20
Q

What is the Snell’s law?

A

n1sin(x1)+n2sin(x2)

21
Q

Total internal reflection

A

theta is greater than the critical angle

22
Q

sin of the critical angle=

A

1/refractive index

23
Q

super position

A

when two waves of the same type passing through each other

24
Q

Define Coherence

A

Waves emitted from two sourcing having constant phase difference and the same frequency.

25
Q

what does each of the symbols mean in

lamda= ax/D

A

a: slit separation, D: distance fro source to screen, x: separation between light and dark and screen

26
Q

What is node

A

a Point of 0 displacement, 0 intensity and 0 amplitude on a stationary wave

27
Q

What is an antinode

A

a Point of max displacement, max intensity and max amplitude on a stationary wave

28
Q

A stationary wave in a coloumn starts and stops when in a one end closed and a both ends open

A

One open: Starts in middle on one end and top on open

Both open: Starts and ends on edges of tube

29
Q

what does the symbols stand for in:

E=hc/lamda

A

Energy of photon= Planck’s constat x Frequency

30
Q

One electronvolt is

A

the energy transferred when an electron moves through a pd of one volt

31
Q

The photoelectric effects

A

When the electromagnetic radiation hits the surface of a metal causes electrons to be emitted

32
Q

Define work function ( circle with line)

A

The minimum energy required to free and electron from the surface of a metal

33
Q

what do the symbols mean of : hf= (circle line) + Ekmax

A

Energy of a photon= Work function + max KE of emmited electron

34
Q

What is used to diffract electrons

A

polycrystaline graphite