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As Physics Unit 1- Dr Bebb > Equations > Flashcards

Flashcards in Equations Deck (20)
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1
Q

Wave speed

A

c = fλ

c is speed
f is frequency
λ is wavelength

2
Q

Period

…and what is period?

A

T = 1/f

T is period
f is frequency

…The period, T, is the time required for one complete cycle and the unit is seconds.

3
Q

Intensity

…and what is intensity?

A

I = P/4πr2

P- power of the source
r- distance from a point source

… intensity is the power transferred per unit area

4
Q

Stretched string frequency

A

f = 1/2l √T/μ

l is the length of the vibrating string
T is the tension in the string
μ is the mass per unit length of the string material

5
Q

Beat frequency

A

f = f1 - f2

The beat frequency is equal to the difference between the frequencies of the individual strings.

6
Q

Fringe spacing

A

w= λD/s

λ is the wavelength of the light
s is the separation of the slits
D is the distance from the double slit to the screen

7
Q

Diffraction grating

A

nλ = d sin θ

n is the order of the image
λ is the wavelength
d the grating spacing
θ the angle the image makes with a line normal to the grating

8
Q

Half beam width

A

sin θ = λ/a

a is dish aperture diameter

9
Q

Snell’s law

A
n1 sin()1 = n2 sin()2 
n1 and n2 are the absolute refractive indices of the transparent substances 1 and 2.
10
Q

Absolute refractive index of a substance

A

ns = c/cs

c is speed of em waves in a vacuum
cs speed of em waves in the substance

11
Q

Critical angle for two substances

A

Sin0c = n2/n1

12
Q

Refractive index

A

ns = 1/sin0c

13
Q

Photon energy

A

E = hf

E- photon energy
h- Planck constant
f- frequency

14
Q

Einstein’s photoelectric effect equation

A

hf = φ + Ek

h- plancks constant
f- frequency
φ- work function
Ek- maximum kinetic energy of the photoelectron

15
Q

De Broglie wavelength

A

λ = h/mv

h- plancks constant
mv- momentum of the particle

16
Q

Wien’s law

A

λ max T = 0.0029 m K

λ max- wavelength at which most radiation is emitted (the peak of the black body curve)
T- absolute temperature of the body that emits the radiation

17
Q

Hubble law

A

v = Hd

v velocity
d distance of a galaxy from Earth
H Hubble constant

18
Q

Joules to watts

A

watt = joule / second

19
Q

Power

A

Power = Energy/ Time

20
Q

Inverse square law equation

A

Intensity = 1 / d^2