Principles of Instrumentation Cont'd Flashcards
Converting from a larger to a smaller unit.
Converting from a smaller to larger unit.
Multiply
Divide
Kilo
Mega
Giga
Tera
10 3
10 6
10 9
10 12
centi
milli
micro
nano
pico
10 -2
10 -3
10 -6
10 -9
10 -12
What is electrostatic force ?
This is the strongest force found in nature.
attractive and repulsive force between negative and positive charged particles.
Describe electron arrangement in orbitals.
First shell has 2 electrons.
Second shell has 8 electrons.
(however it is made up of 4 orbitals close together that each hold maximum 2 electrons.
What is an isotope?
a version of an element that has the same number of protons but a different number of neutrons.
Amongst electrons, protons and neutrons, only protons with their positive charge determines the element
neutrons do not exert a force.
electrons can leave and bind.
T/F
True
In an atom the distance between the nucleus and the electrons are characteristic or constant.
T/F
True
How can you split white light?
Which one diffracts more, red or blue?
Using a prism
Red due to longer wavelength.
What happens when an electron gets heated?
and how does this relate to the colors of visible light?
Electrons can jump to another orbital releasing or taking in energy.
If a flame or light appears yellow, then yellow is reflected while the other colors, frequencies and wavelengths are absorbed.
Planck’s Equation for energy
E = hf
“E” represents energy
“h” is Planck’s constant
“f” (nu) is the frequency
Planck’s Constant
h
6.63 × 10-34 m2 kg / s
What is an absorption emission spectrum ?
How does this relate to electrons and orbitals?
frequencies of light absorbed and emitted.
radiation is absorbed: electron goes from orbit of lower to higher energy.
radiation is emitted:
from higher to lower orbit.
ΔE = E2 - E1
What does this equation represent?
This is the energy needed to overcome the force exerted on electrons by the nucleus.
So that electrons can jump up or down orbitals
What is electromagnetic radiation?
How do they travel?
refers to the electromagnetic spectrum.
EM waves travel in pulses or photons that contain energy called quantized energy
What is Quantized energy?
concept that energy is not continuous but comes in discrete packets or “quanta.”
light and other forms of electromagnetic waves are made up of tiny particles of energy called photons.
Each photon carries a specific amount of energy, determined by its frequency.
The energy of a photon is given by the equation: E=hf
What is the photoelectric effect ?
light or other electromagnetic radiation strikes a material, typically a metal, causing the emission of electrons from its surface.
What is the Key Observation of the Photoelectric Effect?
Electrons are only emitted (ionization) if the light’s frequency is above a certain threshold, specific to the material.
Valence electrons need less energy to be ionised.
What is a PET scan?
What does it do?
(Positron Emission Tomography)
A PET scanner detects gamma rays to create detailed images of tracer distribution.
What is a positron?
a positively charged particle
that is similar in size and mass to an electron.
it is generated from radioactive decay.
What happens when an electron and positron meet?
positron is an anti-particle of an electron.
When they meet they annihilate each other and release two pulses of gamma rays that travel in opposite directions.
Einstein’s mass-energy equivalence formula.
E=mc 2
A photon can pass through an atom?
T/F
Why?
True
Because of the large amounts of space between electrons and proton center.
