Everything

Question 1

4 kinematic formulas

Answer 1

v=u+at
v^2=u^2+2as
s=ut+1/2at^2
s=1/2(u+v)t

Question 2

Fnet of falling bodies

Answer 2

Fnet=W-F

Question 3

Formulas of force (both impulse and constant mass)

Answer 3

F=dp/dt
F=ma (constant mass)

Question 4

Impulse

Answer 4

p=mv

Question 5

Conservation of momentum

Answer 5

m1u = m1v1 + m2v2

Question 6

Elastic collision

Answer 6

u1-u2=v2-v1
speed of approach=speed of separation

Question 7

inelastic collision

Answer 7

m1v1 +m2u2 = (m1+m2)v

Question 8

Moments

Answer 8

M=FxD
Clockwise moments= Anticlockwise moments

Question 9

Hooke’s law

Answer 9

F=kx

Question 10

Upthrust

Answer 10

U=pvg

Question 11

Work done by force

Answer 11

WD=Fs cos θ

Question 12

Work done ON gas

Answer 12

WD=-Pexternal (△v)

Question 13

Work done BY gas

Answer 13

WD= Pexternal (△v)

Question 14

Kinetic energy

Answer 14

KE=1/2mv^2

Question 15

Gravitational potential energy

Answer 15

GPE=mgh

Question 16

Elastic potential energy

Answer 16

EPE=1/2kx^2

Question 17

Power

Answer 17

WD per unit time
P=Fv

Question 18

Efficiency

Answer 18

useful WD/energy input x100%

Question 19

Angular displacement θ

Answer 19

θ= s/r

Question 20

Angular velocity ω

Answer 20

ω=dθ/dt
=2πf
=2π/T

Question 21

Uniform circular motion v

Answer 21

v=rω

Question 22

Centripetal acceleration Ac

Answer 22

Ac=v^2/r
=rω^2

Question 23

Centripetal force Fc

Answer 23

Fc=mv^2/r
=mrω^2

Question 24

Gravitational force of attraction between 2 masses

Answer 24

F= Gm1m2/r^2

Question 25

(GRAV FIELD) Relationship between T and r?

Answer 25

T^2 ∝ r^3

Question 26

Gravitational field strength g

Answer 26

g=Gm/r^2

Question 27

Weight at poles of earth vs equator

Answer 27

At poles, W=N At equator, Fc=W-N

Question 28

Gravitational potential Φ

Answer 28

Φ=-Gm/r

Question 29

Potential energy on mass in grav field

Answer 29

Ep=mΦ

Question 30

Escape velocity and derivation

Answer 30

v=squareroot(2Gm/R) derived from Ekinit=m△Φ

Question 31

Energy needed for mass to reach infinity

Answer 31

TE=0

Question 32

KE of orbiting mass

Answer 32

F between 2 masses= Fc Gm1m2/r^2 = mv^2/r

Question 33

Differences between in phase and out of phase? △Φ (phase diff)

Answer 33

in phase, △Φ=0 out of phase, △Φ=180 or π

Question 34

Angular frequency θ

Answer 34

θ=2πf =dθ/dt

Question 35

Simple harmonic motion acceleration a

Answer 35

a=-ω^2x

Question 36

Horizontal spring F

Answer 36

F=-kx

Question 37

In a horizontal spring system what is ω?

Answer 37

ω=squareroot (K/m) as a=-(K/m)x

Question 38

In a pendulum, what is ω？

Answer 38

ω=squareroot (g/L) as a=-(g/L)x

Question 39

(graph) formulas for displacement, velocity and acceleration for Simple harmonic motion

Answer 39

x=x0 sin wt v=wx0 cos wt a=-w^2x0 sin wt

Question 40

general velocity formula for SHM

Answer 40

±ω squareroot (x0^2-x^2)

Question 41

KE of SHM displacement

Answer 41

KE=1/2mω^2 squareroot (x0^2-x^2)

Question 42

PE of SHM displacement

Answer 42

PE=1/2mω^2 x^2

Question 43

Graphical formula of PE energy-time graph

Answer 43

PE=1/2m(ω^2)(x^2)

Question 44

Graphical formula of KE energy-time graph

Answer 44

KE=1/2m(ω^2)(x0^2-x^2)

Question 45

Graphical formula of TE energy-time graph

Answer 45

TE=1/2m(ω^2)(x0^2)

Question 46

Speed of EM waves

Answer 46

c=3.0 x 10^8

Question 47

Intensity formula and is proportional to??

Answer 47

I=Power/Area I∝Amplitude^2

Question 48

Power formula (intensity)

Answer 48

P= E/t

Question 49

Malu's Law (intensity/polarising)

Answer 49

I=I0 cos^2 θ I∝cos^2 θ

Question 50

Single slit diffraction formula

Answer 50

sin θ= λ/b b is slit width

Question 51

Rayleigh's criterion (2 sources of light)

Answer 51

θ= λ/b =s/r s is the dist between 2 sources r is the dist between slit and source

Question 52

Double slit

Answer 52

x= λD/a x is fringe sep a is slit sep D is total dist from source to slit

Question 53

Diffraction grating

Answer 53

d sin θ= n λ d is slit sep n is order

Question 54

Fixed end vs free end (which one is in phase and which is antiphase)

Answer 54

Fixed end is in phase while free end is antiphase

Question 55

Stationary waves 2 free end/fixed end formula for Length and frequency

Answer 55

L=n(λ/2) F=n(V/2L)

Question 56

Stationary waves 2 free end/fixed end formula for Length and frequency

Answer 56

L=n(λ/2) F=n(V/2L)

Question 57

Electric field strength E at a point in the field

Answer 57

E=F/Q OR F=EQ

Question 58

Electric field strength of uniformed field between charged parallel plates

Answer 58

Question 59

Electric field strength of point charge in air

Answer 59

Question 60

Electric force Fe

Answer 60

Fe= Eq

Question 61

Coulomb’s law

Answer 61

Question 62

Electric potential energy U Positive and neg meaning

Answer 62

U=QV Pos U: wd on field Neg U: wd by field

Question 63

Change in electric potential energy

Answer 63

△U=Q△V =Q(Vf-Vi)

Question 64

Electric potential due to point/sphere charge

Answer 64

Same as electric field strength of point charge but instead of r^2 its just r this time

Question 65

Electrical potential energy of 2 isolated point charges

Answer 65

Question 66

Electric potential of multiple point charges

Answer 66

Vtotal=V1+V2+V3

Question 67

Electric potential energy of multiple point charges

Answer 67

Question 68

Steps to curve sketching for Resultant electric potential graph and resultant electric field strength graph

Answer 68

1. Find magnitude of changes 2. Find location of 0 field strength when E=0 3. Find potential at zero field strength 4. Find field strength at surface of spheres

Question 69

Graph eqn I of AC

Answer 69

I=I0 sinwt

Question 70

Why does heat dissipate in ac?

Answer 70

* power dissipated in resistor * P proportionate to current square because P=I2R OR * ac current change direction every half cycle but direction is independent of current direction

Question 71

Finding RMS value in AC

Answer 71

1. Square function/graph 2. Average value 3. Square root avg value in 2

Question 72

What is RMS value definition?

Answer 72

RMS of steady direct current dissipates thermal energy at the same avg rate as resistor as ac in a given resistor

Question 73

AC Formula of 《I\> *vs* Irms difference*?*

Answer 73

area/T = average current *squareroot (squared area/T) =Irms*

Question 74

AC sinosoidal easier formula

Answer 74

Irms= I0/squareroot 2 Vrms=V0/squareroot 2

Question 75

## Footnote Power of ac circuits

Answer 75

Pavg=Irms Vrms

Question 76

Pheat of AC

Answer 76

Pheat=I2Rcable

Question 77

Explain EMI and transformer input

Answer 77

1. B field generation 2. Change 3. Flux linkage 4. Faraday's law

Question 78

Ideal transformer

Answer 78

Pinput=Poutput

Question 79

Graph eqn of V om AC （for ac-dc rectification)

Answer 79

Vac=V0 sin wt

Question 80

Equipotential lines definition

Answer 80

lines joining points in a field with same potential ALWAYS meet electric field lines at right angles (ie equipotential lines are perpendicular to electric field lines)

Question 81

What happens when charge is moved along an equipotential line

Answer 81

no work is done

Question 82

Relationship between electric field strength and electric potential

Answer 82

[MAG] electric field strength E is numerically equal to the electric potential gradient (dV/dr) at a point in the field [DIR] neg sign shows direction of field strength, pointing to lower potential

Question 83

Electric potential gradient

Answer 83

dV/dr only add negative for E=-dV/dr, where direction is needed

Question 84

Electric force using electric potential

Answer 84

F=-dqV/dr =dU/dr U=qV

Question 85

Unknown temp for thermometric property of empirical centigrade scale

Answer 85

Question 86

Absolute temp from celsius

Answer 86

K=C+273.15

Question 87

Celsius to absolute temp

Answer 87

C=K-273.15

Question 88

Ideal gas law for moles of gas

Answer 88

pV=nRT

Question 89

Ideal gas law for particles of gas

Answer 89

pV=NkT

Question 90

One mole

Answer 90

6.02 x 10^23 One mole of H atoms weigh 2g and 0.002kg

Question 91

Explain/prove pV=⅓Nm (basic idea)

Answer 91

1. change in momentum 2. N2L, F on 1 particle 3. N3L F on wall opposite to F on gas particle 4. Average F over area for MANY collisions from many particles in a random distribution

Question 92

Explain/prove pV=⅓Nm (LONG WORKING)

Answer 92

Question 93

KE of gas particles

Answer 93

=3/2 kT KE directly prop to T

Question 94

Specific heat capacity C

Answer 94

c=Q/m△T basically Q=mc△T

Question 95

Specific latent heat L

Answer 95

L=Q/m

Question 96

Internal energy of a gas U

Answer 96

U= KEsum + PEsum

Question 97

Internal energy of an ideal gas U

Answer 97

Uideal= KEsum + 0 because PEsum is 0 or Uideal = N = 3/2 NkT =3/2nRT =3/2pV

Question 98

First law of thermodynamics

Answer 98

△Uincrease= Qto + Won overall energy = heat + pressure

Question 99

WD on gas

Answer 99

WDon = -Pext△V

Question 100

Answering framework for thermodynamics and internal energy U

Answer 100

Microscopic vs Macroscopic KE (temp) PE (V, phase)

Question 101

WD on p-V graphs

Answer 101

Area under graphs

Question 102

p-1/V graph for isothermal?

Answer 102

linear graph of p=nRT(1/V)

Question 103

Magnetic flux Φ (FOR AREA)

Answer 103

Φ= Bperpendicular A = (B cos θ) A = BA cos θ

Question 104

Magnetic flux linkage (FOR SOLENOID COIL)

Answer 104

NΦ = N(BA) = N(B cosθ)A = NBA cosθ

Question 105

Induced electromag induction at a particular point

Answer 105

Einduced= -d(NΦ)/dt = -d(NBA cosθ)/dt

Question 106

AVERAGE Induced electromag induction

Answer 106

Eave= △Φ/△t

Question 107

Layman EMI vs EM

Answer 107

EMI: Kinetic to electrical EM: Electrical to Kinetic

Question 108

Explaining EMI induction framework

Answer 108

1. Field 2. Change/cut 3. Linkage 1. Faraday's law

Question 109

Explaining eddy currents and damping

Answer 109

1. Explain why emf is induced in the disc 2. Explain why eddy currents are induced 3. Explain why the disc comes to rest after a few oscillations

Question 110

Constant current I

Answer 110

I=Q/t Q=It

Question 111

Current definition and d?/d?

Answer 111

rate of flow of charge dQ/dt

Question 112

Drift velocity v for current carrying conductor

Answer 112

I =nAvq

Question 113

Proving drift velocity formula

Answer 113

Question 114

Potential difference pd

Answer 114

V=W/Q

Question 115

Power supplied by source

Answer 115

P =I**_total**E =I**_total**^2R**_total**

Question 116

Power output of component

Answer 116

P=I**_device**V =I^2R**_device**

Question 117

Resistance

Answer 117

R=V/I

Question 118

Resistance (the wire area etc)

Answer 118

R=pL/A

Question 119

Terminal pd (internal resistance)

Answer 119

Vt= E - Ir

Question 120

Efficiency

Answer 120

Eff= P_load/P_source =I2R_load/I2R_total =R_load/R_load+r

Question 121

How to increase efficiency?

Answer 121

minimise internal R of source OR maximise R of component

Question 122

Efficiency at max power

Answer 122

50% eff

Question 123

Maximum power transfer theorem

Answer 123

Rext same as Rint of EMF source

Question 124

Resistors in series

Answer 124

Reff= R1 + R2 + … +Rn

Question 125

Resistors in parallel

Answer 125

1/Reff = 1/R1 + 1/R2 + … + 1/Rn OR Reff= RaRb/Ra+Rb

Question 126

Potential divider rule

Answer 126

Vout/Vtotal = R/Rtotal

Question 127

Potentiometer circuit formula

Answer 127

V**_tapped**/V**_total** = L**_tapped**/L**_total** = R**_tapped**/R**_total**

Question 128

Balanced conditions of a potentiometer

Answer 128

V_PJ=V_QR 0=I_PQ=I_RJ No current. Length of PJ is the balanced length

Question 129

Mag flux density of a long straight wire

Answer 129

B=µI/2πd

Question 130

Mag flux density of a flat circular coil

Answer 130

B=µNI/2r N is no of turns PER UNIT LENGTH and NOT NO OF TURNS

Question 131

Mag flux density of a lomg solarnoid

Answer 131

B=µnI

Question 132

Mag force in a wire

Answer 132

F=BILsinθ B is perpendicular! F on 1 by 2= B2 I1 L1

Question 133

Mag force of charge particle

Answer 133

F= BQv sinθ Bev sinθ for electron!

Question 134

F on charge moving in a circular field

Answer 134

equate Fb=Fc to get Bqv sin 90=mv^2/r (find r) or =mrw^2 (find T)

Question 135

Magnetic field into vs from paper

Answer 135

Into: clockwise From: anti-clockwise

Question 136

Energy of 1 photon

Answer 136

E=hf =hc/λ

Question 137

Relation of energy of photon and wavelength

Answer 137

Energy decrease when wavelength increase

Question 138

Photoelectric eqn

Answer 138

hf= Φ+½mv_max^2

Question 139

eV to joules

Answer 139

1eV=1.6 x 10^-19

Question 140

Threshold frequency

Answer 140

minimum freq for emission hf=Φ (basically the ½mv^2=0 and emitted e have no energy because energy is only for emission) E is emitted when hf\>Φ and ½mv2\>0

Question 141

Stopping potential quantum physics Vs

Answer 141

eVs= ½mv_max^2

Question 142

Saturation current graph sketching

Answer 142

``` y axis (current i): ne/t Intensity of light proportional to rate of arrival n/t Intensity= Nhf/tA I=P/t =(Q/t)(1/A) =(nE/t)(1/A) ``` X axis (Voltage V): hf=Φ+½mv^2 X axis intersect: KEmax= eVs

Question 143

Deexcitation and excitation of electron

Answer 143

Excitation: hf=|Ef-Ei| absorption spectra, photon is absorbed during upgrade Deexcitation hf=Ef-Ei emission spectra, photon is emitted during downgrade

Question 144

Answering the spectra qns for quantum

Answer 144

1. Define spectrum 2. atom and photon movements, energy levels 3. emit/absorb 4. transit energy direction 1. resultant observation

Question 145

2 components of ouput Xray spectrum

Answer 145

1. characteristic peaks 2. broad continuous bg KE loss=Ephoton qeV=hf=hc/λmin

Question 146

Wavelength for particle (wave-particle duality) when momentum is given

Answer 146

λ =h/p =h/mv

Question 147

Heisenburg uncertainty principle

Answer 147

△p△x \> h MUST BE IN THE SAME DIMENSION

Question 148

Nuclear binding energy

Answer 148

E=△mc2 =(total rest mass of reactants-total rest mass of products) c2

Question 149

energy released in a nuclear reaction

Answer 149

total binding energy of products--total binding energy of reaction = (total rest mass of reactants-total rest mass of products) c^2

Question 150

Charges of alpha beta gamma

Answer 150

A +2e B -e Gamma 0

Question 151

Ioinising power of alpha beta gamma

Answer 151

A strong (larger mass, more charge) B moderate Gamma weak

Question 152

penetrating power of alpha beta gamma

Answer 152

A low B medium Gamma high

Question 153

Nuclear eqn of alpha beta gamma

Answer 153

A gives out ^4₂H B gives out ^0_-1e Gamma gives out y with unchanged original reactant

Question 154

Activity of radioactive decay/rate

Answer 154

A=λN A= -dN/dt λ decay constant and A the rate of decay

Question 155

half life t½

Answer 155

t½+ ln 2/λ N=N₀(½)ⁿ N/N₀= A/A₀ = e^-λt