Physics of Waves and Radiation

Study Notes

Radio wave, Microwave, Infrared, and Visible Light are types of non-ionizing radiation.

Measured by how many complete waves pass a fixed point in a certain amount of time.
Frequency has an inverse relationship with wavelength: Higher frequency = Shorter wavelength.
Wave speed (r) = Frequency (Hz) x Wavelength (m).

Slinky Wave: energy is being transferred back and forth.
Transverse Wave: frequency has an inverse relationship with wavelength.
Rarefaction: wave enters a new medium at an angle, causing bending of waves due to a change of speed.
Reflection: object or wave hits a surface through which it cannot pass, it bounces back.
Diffraction: wave moves around/through an opening in a barrier, it bends and spreads out.
Interference: occurs when two or more waves meet while traveling through the same medium.
- Constructive – Combine wave, continues.
- Destructive – When crest meets trough, they cancel.
Standing Wave: incoming waves/reflected waves with the right frequency produce a wave that looks standing still.

Produced in two ways:
- Incandescence: caused by heat.
- Luminescence: caused by the movement of atoms.
Types of Luminescence:
- Chemiluminescence: chemical reaction.
- Bioluminescence: caused by organisms.
- Fluorescence: light ceases when external excitation stops.
- Phosphorescence: persists even after the removal of external excitation.
Types of Eclipse: Lunar and Solar.
Brightness of light:
- Photometry: measures luminous intensity (I) in cd (Candela) and luminous flux (f) in Im (Lumens).

Disorders:
- Osteoporosis: mineral density of the bone is reduced, making it brittle and porous.
- Goiter: abnormal enlargement of the thyroid gland.
- Gigantism: abnormal increase in height associated with too much secretion of growth hormones.
- Dwarfism: growth hormones in the pituitary gland are insufficient, resulting in short stature.
Glands:
- Adrenal: affects metabolism, immune system, and blood pressure, stress reaction.
- Pancreas: regulates blood sugar levels, reproductive.
- Pineal: regulates the biological clock in some animals.

Phases:
- Follicular phase: starts on day 1 of menstruation, ends with ovulation (day 14).
- Luteal phase: from the day after ovulation to the day before the next period.
Hormones:
- Estrogen: produced by FSH, thickens the endometrium (uterine lining).
- Luteinizing Hormone (LH): released when estrogen peaks, triggers ovulation.
- Progesterone: produced by corpus luteum, prepares the uterus for a fertilized egg.

Evidence:
- Fossil record: provides direct evidence for evolution, shows variation in time.
- Comparative anatomy: homologous and analogous structures, vestigial structures.
- Embryology: ontogeny summarizes phylogeny.
Theories:
- Jean Baptiste de Lamarck: proposed that organisms change over time in response to their environment.
- Theory of Need: organisms change in response to changes in their environment.
- Theory of Use and Disuse: organs that are not used will disappear, while those that are constantly used will develop.
- Theory of Acquired Characteristics: organisms can pass on characteristics they acquire through use or disuse.

Characteristics:
- Made up of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur.
- Polymers of amino acids, arranged in a chain called polypeptide.
- Classified into primary, secondary, tertiary, and quaternary levels.
Functions:
- Help form many structural features of the body.
- Act as catalysts, enabling cells to carry out chemical reactions.
- Maintain proper concentration of ions and molecules for cells to function normally.

Characteristics:
- Composed primarily of carbon, hydrogen, oxygen, phosphorus, and sulfur.
- Hydrophobic nature dictates many of their uses in biological systems.
Types:
- Fats: a good source of stored energy.
- Oils: used to form protective layers on the skin, preventing infection.
- Waxes: used to form protective layers on the skin, preventing infection.
- Steroid hormones: implicated in cancers of the female reproductive system.

Characteristics:
- Capable of being broken down to yield phosphoric acid, sugars, and a mixture of organic bases (purines and pyrimidines).
- Naturally occurring chemical compounds.