4.2 The Different Types of Energy

Describe energy transfers involving  the following forms of energy: thermal (heat), light, electrical, sound, kinetic, chemical, nuclear and potential (elastic and gravitational)

The Nine types of energy that we should know are: (as mentioned in the syllabus statement)

• Thermal (heat) energy
• Light energy
• Electrical energy
• Sound energy
• Kinetic energy
• Chemical energy
• Nuclear energy
• Elastic Potential energy
• Gravitational Potential energy

3.25 Digital signals can carry more information.

Describe how digital signals can carry more information


Digital signals are capable of carrying more information than analogue signals because digital signals make use of the bandwidth more efficiently by closely approximating the original analogue signal...

Exam Correction list & things I need to remember

.... the majority of the time I simply didn't read the question properly or didn't think about my answer enough... but the places where i genuinly screwed up are....

1. Things that affect the size of the current:
     Resistors
     Battery/power supply
2. In physics write things to the same d.p or s.g.f as in the question... and ignore the years of intense training your math teacher has put you through to make you write everything to 3s.g.f and degree's to 1 d.p.

DONE!....Well that was easy.

3.24 Advantages of Digital signals

Describe the advantages of using digital signals rather than analogue signals.

When a signal is transmitted from one place to another it gains noise, noise is where the signal becomes distorted during transmission. In analogue signals distorted signals can not be regenerated into their original form because it is impossible to calculate what it originally looked like. But because digital signals only have a value of 1 or 0 if they were distorted it is quite obvious as to there previous value... as shown in the below diagram.

3.23 Analogue and Digital

Understand the difference between analogue and digital signals.

An Analogue signal is continuous in time and value, this means that it can have any value at any one time.

On the other hand Digital signals are discrete and only have values of either 1 or 0.

3.22 Critical angle and refractive index

Recall and use the relationship between critical angle and refractive index:

c is the critical angle (in degrees,°)
n is Refractive index (no units)

Examples:

What is the refractive index of glass that has a critical angle of 42°?

What is the critical angle for diamond? (Refractive index of diamond = 2.4)

3.21 Critical angle

Recall the meaning of critical angle 


The Critical angle is the smallest angle of incidence for which Total Internal Reflection occurs. So if the angle of incidence is larger than the critical angle total internal reflection will occur.