Notes, summaries, assignments, exams, and problems for Physics

Properties of Laser Light

1. Monochromaticity

Unlike discharge lamps that emit on all atomic transitions, laser emission typically corresponds to a single atomic transition of the gain medium. The spectral line width can be much smaller than the atomic transition's due to the influence of the optical cavity.

2. Coherence

Laser beams exhibit high spatial and temporal coherence.

Spatial coherence describes the regularity of the optical phase across a beam's cross-section.

Temporal coherence refers to the duration over which the beam's phase remains well-defined. The temporal coherence time (t_c) is generally the reciprocal of the spectral linewidth (ν). Consequently, the coherence length (l_c) is: l_c = ct_c = c/ν.

3. Directionality

A key characteristic... Continue reading "Properties of Laser Light: Monochromaticity, Coherence, and More" »

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What is force?

A force is a push or pull that can change the shape of an object the way that it moves. It also changes Speed and direction. You can not see. When something is moving or speeding, the force is acting.

Force arrows:

You can draw an arrow, the length of it, shows the size of force and the direction shows where is coming from.

Types:

The gravitational force, is the force that attracts you to Earth. In the earth, the force of gravity in a object is called Weight.

Electrostatic:

It acts between objects that are charged. Rubbing plastics can charge them up with electricity.

Magnetic: The magnets attract materials such as iron, steel, or nickel.

Friction:

When any object slides across a surface, the force of friction tries to stop it moving.

Lens

What is a real image?

An image where real rays intersect

What is a virtual image?

An image that appears to be coming from behind the mirror

Describe the law of reflection as a relationship between the angle of incidence, the angle of reflection, and the normal.

The angle of incidence, angle of reflection and normal all lie in the same plane

Describe the kinds of images that can be formed by plane mirrors.

Only virtual images, little distortion

What type of mirror produces only diverging rays?

Convex

What type of mirror can produce both converging and diverging rays?

Concave

Describe what kind of mirror you would use if you needed to view a large, spread-out area in a small mirror.

Convex

Compare the shapes of convex and concave mirrors. How are they

Key Benefits of Using Solar Power

• Clean energy
• Renewable energy

Future of Photovoltaic Systems in Industrial and Developing Countries

Does the future hold a place for photovoltaic (PV) systems in both industrial and less developed countries?

Yes, because the problem of CO2 emissions is getting bigger, and it is necessary to invest immediately in new sources of renewable energy.

Advantages of Off-Grid PV Systems for Emergency Applications

What are some advantages of using off-grid PV systems for emergency call boxes and emergency warning signals?

• They save the cost of extending power lines to far-away locations.
• In the event of an electrical failure, they will still function.

Major Disadvantage of PV Systems

PVs require light to operate. What is one big

True/False

t: A strong acid is one that will completely ionize

f: When blue litmus paper is placed in a weak acid, it will turn a darker shade of blue

f: When pH paper provides a reading which says it has a pH of 9, the substance is considered a weak acid.

f: Alpha, Beta, and Gamma are all forms of nuclear radiation that contain either positive or negative charges.

t: Fission is the process where a large nucleus splits unto two smaller nuclei.

f: The most common isotope of carbon that is used for radioactive dating is carbon-13.

t: Static friction is friction that occurs when an object is not moving.

f: When an object is accelerating but it is not traveling in a straight line, it must be moving vertically.

t: Friction is force that always opposes the... Continue reading "Science True/False and Multiple Choice Questions" »

Thermal Energy

Thermal energy is the average kinetic energy of the atoms or molecules in a substance.

Thermal Energy and Changes of State

When a change of state occurs, the energy transferred in heating up the substance is used to break the bonds between the molecules. The energy transferred does not increase the thermal energy but rather increases the internal energy of the substance.

Key Concepts

• The particles of a substance are in constant motion, and this increases as the substance heats up.
• Thermal energy is the average kinetic energy of the particles of a substance.
• During a change of state, the energy transferred in the heating process is used to break the bonds between molecules without increasing its thermal energy.

Temperature: Measurement

Angular Kinetics

Center of Mass

Point around which mass or weight is considered to be concentrated.

Determining COG

• Balance method
• Suspension method
• MRI reconstruction
• Segmental

Segmental Limitation

• Based on Caucasian male cadavers
• Completed in 1930s
• Based on segments being truncated cones

Mechanical Stability

Ability to maintain vertical projection of CG within base of support.

Ways to Increase MS

• Increase mass
• Increase friction between body and surface
• Increased size of base support

Angular Inertia

Property of an object to resist changes in its angular motion.

Factors Influence

Radius has larger influence than mass.

Center of Mass

Point where gravitational force is applied balance

Radius of Gyration

Point where mass can conceptually be concentrated such that it does... Continue reading "Angular Kinetics and Biomechanics" »

It is the view that our mind and our brain are different things. One way to understand this concept is to consider our self as a container including our physical body and physical brain along with a separate non-physical mind, spirit, or soul. The mind, spirit, or soul is considered the conscious part that manifests itself through the brain in a similar way that picture waves and sound waves manifest themselves through a television set. The picture and sound waves are also non-material just like the mind, spirit, or soul.

Elements of Design

1. Lines

• Vertical lines: Create height and grandeur.
• Horizontal lines: Establish relationships and calm the mood.
• Diagonal lines: Generate movement and direction.
• Curved lines: Convey familiarity, comfort, and relaxation.
• Thick lines: Direct the eye without distraction.

2. Shapes

3. Color

4. Value

5. Texture

6. Space and Perspective

Principles of Design

1. Space

2. Alignment

3. Repetition

4. Contrast

5. Pattern

6. Rhythm and Movement

7. Proportion

8. Balance

9. Unity

10. Emphasis

Principles of Design

1. Similarity

2. Continuation

3. Closure

4. Proximity

5. Figure

6. Symmetry

Anatomy of the Eye

The retina of the eye, lining the posterior two-thirds of the eyeball, is located within the inner tunic.

The jelly-like substance located between the lens and retina is the vitreous body.

True or false: Accommodation refers to the change in lens thickness in order to provide fine focus of an image. The answer is true.

Functions of the Vitreous Body:

• Maintains shape of eyeball
• Refracts rays of light
• Keeps retina smoothly pressed against inner surface of eye chamber

Hemidecussation occurs within the visual projection pathway at the optic chiasm.