Flashcards in Understanding Processes Deck (65):

1

## How can you half the period of a wave

###
Double the frequency

Half the wavelength

2

## If 3 identical phasers with an amplitude of A super impose in phase what will the new amplitude be?

### 3A

3

## What does 1 rotation of a phasor indicate

### 1 complete wavelength

4

## Why does for exerted by a spring reduce as it recoils?

###
Friction

Tension reduces as it moves forward

5

## Why repeat readings?

###
Identify as outliers

Mean value is better then any specific value

Reduces uncertainty

Identifys range

6

## How can you work out the probability of a photon arriving?

### Intensity * (Phasor Amplitude)^2

7

## How do satellite dishes increase the probability of signal being received?

### They have a curved dish to create many paths of equal length

8

## What is the unit for electric field strength and magnetic field strength?

###
NC-1

Wb m-2

9

## What makes ceramics brittle?

###
They contain atoms bonded in random positions leaving no slip planes

Cracks spread as stress is concentrated at the top of the crack

10

## When analysing a graph what should you look for?

###
Gradient

Change In gradient

Y intercept

11

## How do you deduce absolute uncertainty of a equation?

### What out the maximum possible value and use minus it from the normal value

12

## What equations should be used when formulating equations for projectiles

### SUVAT

13

## Give examples of systematic errors

###
Starting a stop watch at the wrong time

Measuring using a roller without 0 at the end

Measuring the hight at the top of an object instead of at the bottom

Uncalibrated equipment (0 error)

14

## How can you justify number of significant figures?

###
Find uncertainty

1 s.f above you loose info

1 s.f below you not justified as you round to uncertainty

15

## Why would one use one values uncertainty for an equation but no another values

### Compare uncertainties and their effects

16

## How can you calculate thrust?

###
Thrust = Force + Weight

= Mg + Ma

17

## How can the photo electric effect prove the quantum behaviour of light

###
Energy required to free an electron

Higher f/Lower Wavelength means higher photon energy

Increasing intensity doesn't mean electrons are emitted if the f is too low

1 photon frees one electron

18

## How can the work function be calculated

###
E = hf

where e is the work function

19

## What should you say when asked my a calculated value is off

### Value used in a equation is too high/low, because reason (diffuclt to measure etc.)

20

## Why would electron diffraction (WL=4nm) be more suitable for studying arrangement of atoms of spacing 0.1nm then light diffraction (WL=600nm)

###
Wavelength needs to be less than or equal to gap spacing for diffraction

Electron diff is closer to smaller atomic distances

21

## Why is no work done when force is at right angles to direction of motion

###
Work = Force * Distance (in direction of force)

Distance in direction of force is 0 so no work is done

22

## What is doping of Semi Conductors

### When impurities are added to semi conductors to change there properties like conductivity

23

## Why do metals resistance increase as it heats up

###
As the metal heats up, the atoms inside vibrate,

The Kinetic energy of the atoms is proportional to T (kelvin)

The electrons traveling as charge have the same amount of KE as the atoms, but as they are lighter they vibrate more

This vibration causes collisions in the metal structure, resting the travel of electrons

24

## Why do semi conductors resistance decrease as it heats up

###
When the semi conductor heats up, the atoms inside vibrate

However, when heated the thermal energy causes electrons to be promoted from the valency band to the conducive band increasing the number of charge carriers

The effect of the promotions is greater then the effect of the vibration, so the resistance decreases

25

## What is an intrinsic material

### One that is completely pure without impurities

26

## What is an extrinsic material

### One that has had impurities added

27

## What are superconductors

### Materials with 0 resistance

28

## Why when calculating a value from an iterative graph why it it always an estimate, and why will a formula produce a different result

###
There is a lack of precision in the graph, where as:

formula has effectively infinite number of steps

not enough steps in the iterative calculation

time interval too long in iterative calculation

each iteration assumes constant speed

29

## When made up of multiple wavelengths of light, which wavelength will diffract the the most when shone through the slit

### The greater the wavelength, the greater the angle of diffraction

30

## What is the first harmonic wavelength on a tube with one open side and one closed

### λ/4

31

## To how many significant figures is an uncertainty

### 1 s.f

32

## When plotting 1/v to 1/u how can you find 1/f

###
x intercept

1/v=0+1/f

33

## How can you find e/kT using experimental data

###
Linerise the equation:

Ln N = -e/k(1/T) + Ln N0

Plot the graph of y = mx + c

The gradient is e/kT

34

## How can work done by a moving weight falling into the ground and digging in slightly

### GPE = m*g*h where h is the total distance moved

35

## What happens to light patterns when the slit is doubled I n distance

### Seperation halfs, intensity doubles

36

## Why are sound changes easier to detect outside then in a laboratory

### Less reflection outside, meaning fewer standing waves

37

## A 50w filament build produces the same brightness as a 5w LED. If they are 100% efficient, what does this suggest about the nature of the filament photons

###
Most/45W of the output of the filament lamp is not visible

Filament emits photons of lower frequency

38

## How can you convert watt hours to joules

### Multiply it by 60 squared

39

## How can you find the curvature of waves leaving a lens

### Curvature before + Power of lens

40

## How can you find total conductance of 2 components in series and parallel

###
Series: 1/Ca+1/Cb=1/Ct

Parallel: C1 + C2 = Ct

41

## How can you compare compression strength and tension strength

### Stress at Tension BP/Stress at Compression BP

42

## How can you calculate spread

### Spread is half the range

43

## How can you calculate an outlier

### An outlier is greater or less than 2x the range from the mean

44

## What are the equations for voltage on a charging and discharging capacitor

###
Charging: V=Vo (1-e^(-t/RC))

Discharging: V=Vo e^(-t/RC)

45

## What are the equations for current on a charging and discharging capacitor

###
Charging: I=Io e^(-t/RC)

Discharging: I=Io e^(-t/RC)

46

## What are the equations for charge on a charging and discharging capacitor

###
Charging: Q=Qo (1-e^(-t/RC))

Discharging: Q=Qo e^(-t/RC)

47

## What is the time constant for a charging or discharging capacitor

###
t=RC

Charging: The time taken for the change on the capacitor to reach (1-1/e)Qo

Discharging: The time taken for the change on the capacitor to reach 1/e Qo

48

## How can you work out the time taken for a capacitor to reach half charge

###
2=e^(t0.5/RC)

Ln 2 = t0.5/RC

t0.5 = RC Ln2

49

## Why might there not be a second order of maxima during differentiation

###
nλ = dSinΘ

SinΘ is greater then 1

Therefore Θ isn't possible

50

## How can you calculated for exerted by a crash mat if only given work down by falling object and distance of compression

###
Force = Work/Compression Distance

51

## Why mighty a projectile not reach the max speed/height calculated from SUVAT

### Air resistance/Drag provides decreasing force, dissipating energy

52

## How can the number of loops in a wavelength with a frequency X times greater then the fundamental be found?

### Fundamental + X Loops

53

## How can you find there power required to accelerate a vehicle

###
Power = ΔKE/T

= 0.5*M*ΔV^2/t

54

## How can you find force from Kinetic energy

### F = Ek/d

55

## How should wavelength be altered to keep the same angled between maxima if slit width is reduced

### Reduce Wavelength

56

## How can you work out velocity change between 2 vector

### put vector together and find resultant

57

## What equation can be used to improve image contrast

### New Value = (Old Value-Old value Minimum)*(Max Possible/Old Range)

58

## Why are capacitor energy equations halved

###
Energy = Area Under QV Graph

= 1/2 CV

59

## If a bright image is produced by a diffraction gratin, what are the wave crests like on the wavelets

### All in-phase

60

## Imagine a trolly connected to 2 springs either side of it. explain why the system is simple harmonic

###
Force is DP to Displacment

Force id DP to Acceleration - Newtons second Law

Acceleration is in opposite direction to displacement

61

## How does a standing wave form

###
Identical waves traveling in opposite directions super impose

Leading to constructive interferences (producing antinodes) and destructive interference (producing nodes) if the waves are in phase

62

## If there is no amplitude in the middle of a standing wave, what does it tell you about the waves leaving the source

### they are in anti phase as they leave the source

63

## Suggest a practice use for an photo electric cell other then solar pannels

### Automatic light sensing switch, however surface needs to be clean and only works for certain wavelengths of light

64

## What effects does alloying a metal have and why

###
Harder, stiffer, less ductile more brittle as

Dislocations allow layers of atoms to move over each other by breaking one bond at a time producing plastic deformation

Alloying pins dislocation stopping them from travelling through the structure

Allowing for stress to be concentrated in the material making it more brittle

65