Physis - Equations

Question 1

E = F / Q

Answer 1

Electric field strength = Force / Charge

- Force per unit positive charge

Question 2

F = Qq / 4piEor^2 (Coulomb’s Law)

Answer 2

Force = Charge 1 x Charge 2 / 4 Pi x permitivity of free space x radius squared

Question 3

V = Q / 4piEor

Answer 3

Electric Potential = Charge / 4pi x permitivity of free space x radius

Question 4

E = V/d

Answer 4

Electric Field Strength = Potential difference / distance

Question 5

energy = Qq / 4piEor^2

Answer 5

energy = chargexcharge / 4pi x permitivity x radius ^ 2

Question 6

F = Bilsin0

Answer 6

Force = Magnetic Flux Density x current x length x sin theta

Question 7

F = BQV

Answer 7

Force = Magnetic Flux Density x Charge x Velocity

Question 8

Φ = BAcosθ

Answer 8

Magnetic Flux = Magnetic Field Strength x Area x Cos 0

Question 9

ℰ = – ∆(NΦ) / ∆t

Answer 9

Electromotiveforce = Change in Number of coils x Magnetic Flux / Time

Question 10

R = r0A1/3

Answer 10

Radius = radius0 x area ^ 1/3

Question 11

A = λN

Answer 11

Activity = Decay Constant x Number of undecayed Nuclei

Question 12

∆N / ∆t = – λN

Answer 12

Change in nuclei / Change in time = Negative decay constant x number of nuclei

Question 13

λt1/2 = ln(2)

Answer 13

Decay constant x half life = Natural log 2

Question 14

A = A0e^–λt

Answer 14

Activity at time = Initial activity x Exponential ^ - decay constant x time

Question 15

N = N0e ^ –λt

Answer 15

Nucleons = initial nucleons x exponential ^ - decay contant x time

Question 16

I = I0e^–µx

Answer 16

Intensity at time = Initial intensity x exponential ^ - linear coefficient x thickness

Question 17

Z = ρc

Answer 17

Acoustic Impedence = Density x speed of sound

Question 18

Ir / Io = (Z2 - Z1) ^ 2 / (Z2 + Z1) ^ 2

Question 19

/\F / F = 2vcos0 / c

Question 20

F = MV^2 / R

Answer 20

Force = Mass x Velocity (squared) / radius

Question 21

F = mω2r

Answer 21

Force = mass x angular velocity (squared) x radius

Question 22

a = v ^2 / r

Answer 22

Acceleration = velocity (squared) / radius

Question 23

a = w^2 r

Answer 23

acceleration = angular velocity x radius

Question 24

v = wr

Answer 24

velocity = angular velocity x radius

Question 25

w = 2piF

Answer 25

angular velocity = 2 pi x frequency

Question 26

w = 2pi / T

Answer 26

angular velocity = 2 pi / time period

Question 27

a = -w^2x

Answer 27

acceleration = -angular velocity (squared) x distance

Question 28

x = Acosω t

Answer 28

distance = Amplitude x cos(angular velocity x time)

Question 29

x = Asinω t

Answer 29

distance = Amplitude x sin(angular velocity x time)

Question 30

v = ±ω \/A2 – x2

Answer 30

velocity = +- angular velocity x sqrt (Amplitude(squared) - distance(squared))

Question 31

g = F/m

Answer 31

gravitational field strength = Force / Mass

Question 32

F = –GMm / r^2

Answer 32

Force = - Gravitational constant x Mass 1 x mass 2 / distance (squared)

Question 33

g = –GM/ r^2

Answer 33

gravitational field strength = - graviational constant x mass / radius squared

Question 34

T^2 = (4π2) / (GM) r^3

Answer 34

Time (squared) = 4pi ^2 / (gravitational constant x mass) x radius (cubed)

Question 35

Vg = –GM / r

Answer 35

Velocity = - Gravtiational constant x mass / radius

Question 36

energy = – GMm / r

Answer 36

energy = -Gravitational constant x mass 1 x mass 2 / distance

Question 37

hf = ∆E

Answer 37

plancks constant x frequency = /\ energy

Question 38

hc / λ = ∆E

Answer 38

planks constant x light speed / wavelength = change in energy

Question 39

dsinθ = nλ

Answer 39

distance x sin theta = path difference x wavelength

Question 40

λmax ∝ 1 / T

Answer 40

max wavelength is directly proportional to 1 / temperature

Question 41

L = 4πr 2σT^4

Answer 41

luminosity = 4 pi x radius x 2 stefans constant x temperature ^ 4

Question 42

∆λ/ λ = ∆f/ f = v / c

Answer 42

change in wavelength / wavelength = change in frequency / frequency = potential difference / speed of light

Question 43

p = 1 / d

Answer 43

paralax angle = 1 / distance

Question 44

v = H0d

Answer 44

velocity = hubbles constant x distance

Question 45

t = H0 ^–1

Answer 45

time = hubbles constant ^ -1

Question 46

C = Q/ V

Answer 46

Capacitance = Charge / Potential difference

Question 47

C = ε0A / d

Answer 47

Capacitance = Permitivity of free space x area / distance

Question 48

C = 4πε0R

Answer 48

capacitance = 4 pi x permitivity of free space x resistance

Question 49

C = C1 + C2

Answer 49

capacitance in parallel = c1 + c2

Question 50

1/ C = 1/ C1 + 1/ C2

Answer 50

Capacitance in series = 1 / capacitance, + 1 / capacitance

Question 51

W = 1/ 2QV ; w = 1/2 Q^2 / C ; w = 1/2 V^2C

Answer 51

work done = 1/2 charge x voltage OR 1/2 charge squared / capacitance OR 1/2 potential difference squared x capacitance

Question 52

τ = CR

Answer 52

Time constant = Capacitance x resistance

Question 53

x = x0e ^– t /CR

Answer 53

current value = inital value x exponent ^ - time constant / CR (discharging capacitor)

Question 54

x = x0(1 – e^– t/CR)

Answer 54

current value = initial value x (1 - exponential constant ^ -Time constant / Capacitance x resistant)