Modern Physics - Formula - Level 3 Flashcards

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1
Q

Energy

A

Symbol - E

Units - Joules (J)

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2
Q

Planck’s constant (6.63 x 10^-34)

A

Symbol - h

Units - Joule seconds (Js)

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3
Q

Frequency

A

Symbol - f
Units - Hertz (Hz)
or Seconds inverse (s^-1)

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4
Q

Work function

A

Symbol - Φ

Units - Joules (J)

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5
Q

Kinetic energy of an electron

A

Symbol - Ek

Units - Joules (J)

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6
Q

Charge of an electron (1.6 x 10^-19)

A

Symbol - e

Units - Coulomb (C)

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7
Q

Velocity of electron

A

Symbol - v

Units - Metres per second (ms^-1)

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8
Q

Mass

A

Symbol - m

Units - Kilograms (kg)

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9
Q

Rydberg constant

A

Symbol - R

Units - Meters inverse (m^-1)

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10
Q

Wavelength

A

Symbol - λ

Units - Meters (m)

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11
Q

Speed of light (velocity of radiation) (3 x 10^8)

A

Symbol - C

Units - Meters per second (ms^-1)

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12
Q

Energy value for a given energy level (n)

A

Symbol - En

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13
Q

Energy level number (1, 2, 3 ,…)

A

Symbol - n

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14
Q

Final energy level (first in equation)

A

Symbol - S

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15
Q

Inital energy level (second in equation)

A

Symbol - L

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16
Q

Equation for energy of a photon (from frequency)

A

Epho = hf

Where,
f is the frequency of the incident light

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17
Q

Equation for energy of a photon, when given the wavelength

A

Epho = hC/λ

Where,
λ is the wavelength of the radiation

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18
Q

What is the velocity of radiation equal to?

A

C = λf

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19
Q

Equation for photoelectric effect

A

Epho = Φ + Ek max

Where,
Epho is the energy present in the incident photon
Φ is the work function of the metal surface
Ek max is the maximum kinetic energy of the ejected photoelectron

20
Q

Equation for threshold frequency

A

hfo = Φ

Where,
fo is the threshold frequency
Φ is the work function of the metal

21
Q

Equation for kinetic energy and electrical potential energy

A

hf = hfo + 1/2 me ve^2

Where,
hf is the energy present in the incident photon
hfo is threshold frequency
1/2 me ve^2 is the kinetic energy of the electron

hf = hfo + Ve

Where,
hf is the energy present in the incident photon
hfo is threshold frequency (work function)
Ve is the electrical potential energy

(hfo + Ve = hfo + 1/2 me ve^2)

22
Q

Converting from nano and micrometers to meters

A

Nano x 10^-9

(Mew) Micro x 10^-6

23
Q

Converting from volts or joules to electronvolts

A

(Volts or joules) / (1.6 x 10^-19)

24
Q

Converting from Megahertz to hertz

A

Megahertz x 10^6

25
Q

Calculate the maximum wavelength when given the work function

A

Wavelength is indirectly proportional to frequency
(Max wavelength = Min frequency)

  1. Calculate the threshold frequency (Min frequency)
    hfo = Φ
  2. Calculate the wavelength (Max wavelength)
    λ = C/fo
26
Q

Equation for cutoff voltage from frequency and energy

A

Vo = (hf - hfo)/e

Where,
Vo is the cutoff voltage
hf is the energy present in the incident photon
hfo is the work function

27
Q

Equation for kinetic energy

A

Ek = hf - Φ

Where,
Ek is the amount of kinetic energy that an
electron can have when it is ejected from the
metal after being hit with a photon of light of
frequency f (Hz).
hf is the energy present in the incident photon
Φ is the work function (threshold frequency)

28
Q

Equation for cutoff voltage from kinetic energy

A

eVo = Ek

Where,
Vo is the cutoff voltage

29
Q

Equation for energy of an electron in each level

A

E = -Rch/n^2

Where,
The negative sign indicates that when an atom is formed, energy is released when an electron is brought to an energy level from infinity where energy is zero.

30
Q

Equation for mass deficit

A

△m = mr - mp

Where,
mr is the mass of the reactants
mp is the mass of the products

31
Q

Equation for change energy from mass deficit

A

E = △mC^2

Where,
E is the change in energy
△m is the mass deficit
C is the velocity of the radiation (squared)

32
Q

Equation for the current number of radioactive nuclei

A

N = No(1/2)^n

Where,
No is the original number of radioactive nuclei
N is the current number of radioactive nuclei
n is the number of half-lives

33
Q

Calculate the frequency/wavelength of the radiation emitted by an electron jumping from one level to another

A
  1. Calculate energy difference
    △E = Rch(1/na^2 - 1/nb^2)

Where,
E is the energy difference
nb is the higher energy level number
na is the lower energy level number

  1. Calculate frequency
    E = hf
  2. Calculate wavelength
    λ = C/f
34
Q

Equation for Lyman series

A

1/λ = R(1/1^2 - 1/n^2)

Where, n is the higher energy level number

35
Q

Equation for Balmer series

A

1/λ = R(1/2^2 - 1/n^2)

Where, n is the higher energy level number

36
Q

Equation for Paschen

A

1/λ = R(1/3^2 - 1/n^2)

Where, n is the higher energy level number

37
Q

Equation for binding energy of nucleus

A

E = Rch/n^2

Where,
E is the binding energy
n is the energy level number which the electron has been removed from

38
Q

Calculate the binding energy of an element per nucleon given unit u

A
  1. Write equation of element (either fission or fusion)
    - Number of protons is atomic number
    - Number of neutrons is mass number - atomic number
  2. Calculate the total mass of the nucleons (mass number)
  3. Calculate the total mass of the element
  4. Subtract one mass value from the other to calculate the difference (Mass deficit)
  5. Convert mass deficit from units u, to kg
  6. Calculate the binding energy using E = mc^2
  7. Divide energy value by the number of nucleons in the particle
39
Q

Converting from daltons (u) to kilograms

A

Daltons x (2.66054 x 10^-27)

40
Q

Unit of radioactivity - Curie

A

Symbol - Ci

Units - Decays per second (1 Ci = 3.7 x 10^10)

41
Q

Unit of radioactivity - Becquerel

A

Symbol - Bq
Units - Decays per second
(1 Bq = 1 decay per second)

  • A becquerel is the rate of disintegration of a radioactive subastance
42
Q

Converting from megaelectron volts (MeV) to joules

A

MeV x (1.6022 x 10^-13)

43
Q

Converting from megajojules (MJ) to joules

A

MJ x (10^6)

44
Q

Equation for the number of half-lives

A

n = t/T1/2

Where,
n is the number of half-lives
t is the total time
T1/2 is the time for one half-life

45
Q

Equation for binding energy of nucleus per nucleon

A

Binding Energy per Nucleon = Total Binding Energy of the Nucleus / Number of Nucleons in Nucleus