Spectrum Flashcards
X rays
Greatest penetrating power and they are able to pass through concrete. Produced by energy changes of inner orbital electrons and by the slowing down of accelerating electrons
Gamma rays
Produced by energy changes within the nuclei of radioactive substances. Several cm of lead are needed to stop Gamma rays.
Dual Nature of em radiation
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Wave-like behavior: EM radiation exhibits wave-like properties, such as:
- Diffraction
- Interference
- Superposition
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Particle-like behavior: EM radiation also exhibits particle-like properties, such as:
- Having energy and momentum
- Exhibiting particle-like interactions (e.g., Compton scattering)
- Wave-particle duality: EM radiation can exhibit both wave-like and particle-like behavior depending on the experiment and observation.
- Photon model: EM radiation can be described as consisting of particles called photons, which have energy and momentum.
- Dependence on observation: The behavior of EM radiation (wave-like or particle-like) depends on how it is observed and the experiment conducted.
Photoelectric effect
Emission of electrons from the surface of a metal when the light shines on the metal
Photons
Particles of electromagnetic radiation. It is a particle of light energy. Each photon contains a particular quantity of energy which depends on the frequency of the radiation. The color of light is associated with its frequency. Monochromatic light is light of one particular frequency only(one color only)
The energy of a photon of em radiation is
Directly proportional to its frequency.
Formula for the energy of a photon is calculated
E=hf
H= 6,63 ×10 to the power of - 34
F=frequency
E= energy of photon(J)
What happens when you can’t detect wave motion
Here’s a summary:
Electromagnetic (EM) waves, like light and radio waves, can’t be directly observed like water or sound waves because:
- They have very short wavelengths and high frequencies
- They don’t need a physical medium to travel
- They move extremely fast
- They oscillate electrically and magnetically, rather than physically displacing particles
However, we can indirectly observe EM wave motion using tools like oscilloscopes, spectrometers, and radiation detectors, which help us study and understand their behavior.
Higher frequency
Short wavelength of em
Interference
Interference in Electromagnetic (EM) waves refers to the phenomenon where two or more EM waves overlap in space and time, resulting in a new wave pattern. This occurs when the waves have the same frequency and are in phase (or out of phase) with each other.
Types of interference:
- Constructive interference: Waves in phase, resulting in increased amplitude (brightness or intensity).
- Destructive interference: Waves out of phase, resulting in decreased amplitude (darkness or reduced intensity).
Examples of interference in EM waves:
- Radio wave interference: Overlapping radio signals can cause static or distortion.
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Light wave interference: Creates patterns like:
- Diffraction: Bending around obstacles.
- Radar wave interference: Used to detect and locate objects.
Interference is a fundamental property of EM waves, and understanding it is crucial in various fields like:
- Communication: Minimizing interference in radio and wireless communication.
- Optics: Controlling light interference for applications like lasers and telescopes.
- Radar technology: Utilizing interference to detect and track objects.
Relationship between frequency and energy of em radiation
There is a direct relationship between the frequency (f) and energy (E) of electromagnetic radiation, which is given by the formula:
E = hf
where:
- E is the energy of the radiation
- h is Planck’s constant (approximately 6.626 x 10^-34 J s)
- f is the frequency of the radiation
This equation shows that:
- As frequency increases, energy increases
- As frequency decreases, energy decreases
In other words, higher frequency electromagnetic radiation has more energy, while lower frequency radiation has less energy.
Here’s a rough ordering of electromagnetic radiation by frequency and energy:
- Low frequency:
- Radio waves (long wavelength, low energy)
- Microwaves (medium wavelength, medium energy)
- Medium frequency:
- Infrared (IR) radiation (shorter wavelength, higher energy)
- High frequency:
- Visible light (even shorter wavelength, higher energy)
- Ultraviolet (UV) radiation (short wavelength, high energy)
- X-rays (very short wavelength, very high energy)
- Gamma rays (extremely short wavelength, extremely high energy)
Process of em wave
The process of an Electromagnetic (EM) wave can be described in the following steps:
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Generation: An EM wave is generated by accelerating charges, such as electrons. This can occur in various ways, like:
- Radio waves: Oscillating currents in antennas
- Light: Electrons transitioning between energy levels in atoms
- X-rays: High-energy electrons hitting a metal target
- Oscillation: The accelerated charges create oscillating electric and magnetic fields, which are perpendicular to each other and to the direction of propagation.
- Wave propagation: The oscillating fields propagate through space as a wave, carrying energy away from the source.
- Electric field: The electric field component of the wave oscillates in magnitude and direction, creating an electric field that varies with time and space.
- Magnetic field: The magnetic field component of the wave also oscillates, creating a magnetic field that varies with time and space.
- Wavefront: The wavefront is the surface where the wave has the same phase and amplitude, moving forward with the speed of light (c).
- Transmission: EM waves can travel through a medium (like air, water, or a vacuum) without requiring a physical medium.
- Reception: EM waves are received by detecting the changes in the electric and magnetic fields, using devices like antennas, receivers, or sensors.
- Absorption: EM waves can be absorbed by materials, transferring their energy to the absorbing medium.
This process describes how EM waves are generated, propagate, and interact with matter, enabling various phenomena like communication, heating, and illumination.
Calculating frequency or wavelength
To calculate the frequency and wavelength of EM radiation, you can use the following formulas:
Frequency (f)
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Using the speed of light (c) and wavelength (λ):
f = c / λ
where:
f = frequency (in Hz)
c = speed of light (approximately 3 x 10^8 m/s)
λ = wavelength (in meters)
-
Using Planck’s constant (h) and energy (E):
f = E / h
where:
f = frequency (in Hz)
E = energy (in Joules)
h = Planck’s constant (approximately 6.626 x 10^-34 J s)
Wavelength (λ)
-
Using the speed of light (c) and frequency (f):
λ = c / f
where:
λ = wavelength (in meters)
c = speed of light (approximately 3 x 10^8 m/s)
f = frequency (in Hz)
-
Using the energy (E) and Planck’s constant (h):
λ = hc / E
where:
λ = wavelength (in meters)
h = Planck’s constant (approximately 6.626 x 10^-34 J s)
c = speed of light (approximately 3 x 10^8 m/s)
E = energy (in Joules)
Remember to use consistent units when plugging in values!
These formulas allow you to calculate the frequency and wavelength of EM radiation, given the appropriate values.
Nuclear decays or radioactive decay
High frequency charges released because the nucleus is unstable therefore extra particles in the nucleus are lost in order to attain stability.
Ultraviolet lights
Produced by energy changes in the outer electrons of the atom.
