PART 1
1. The answer is low frequency electromagnetic waves are able to go around obstacles due to their larger wavelengths. This characteristic of lower frequency waves is due to their ability to diffract around obstacles such as buildings and hills. Therefore, they transmit over long distances unlike high frequency electromagnetic waves.
2. One disadvantage is interference. Electromagnetic waves of the same frequency transmitted at the same time will interfere with one other and therefore the signal will be lost or scrambled. Other electromagnetic waves such as microwaves are affected (interfered with) by weather elements.
3. Analogue signals are continuous signals with wave-like properties while digital signals are discrete signals or pulse (ons (1s) and offs (0s) that represent bits). Analogue signal is represented by a sine-wave while digital signal is represented by discrete squares waves.
4. Digital signals are less immune to eavesdropping unlike analogue signals. Analogue signal is also more prone to distortion unlike digital signal. Digital signals transmit more data than analogue signals. Digital signal draw less energy to transmit compared to analogue signal.
5. Broadcasting of TV is nowadays using digital signals due to the high number of available channels. Computers and the interne utilize digital signaling to transmit data. Controls systems such as radar system also use aspects of analogue waves. Sensors also utilize analogue waves especially transducers such as seismology equipment.
PART 2
1. One way is by sending radio waves to probes sent out in space to give them commands during exploration. Radio telescopes also pick up naturally-occurring radio waves from space and analyze the data to make conclusions about space and the astronomical objects.
2. Radio waves are used in communication by transmitting data over long distances. One example is its use TV transmission. Another is through military defense of airspace. The radio waves are used to detect enemy intrusion into restricted airspaces using radar.
3. It is common that signal from the environment will be in analogue signal format. The conversion to digital signals allows for the digital equipment in the telescope to interpret and analyze the data. Telescopes prefer digital equipment because they consume less power, handle more data, and are less prone to intrusion, and distortion, hence more secure to analogue equipment.
<u>Answer</u>: c. Natural gas.
<u>Explanation</u>:
- <em>Natural gas</em> is a fossil fuel and thus a<em> non-renewable resource.</em>
- Natural gas is widely used for the purpose of heating, cooking, and generation of electricity.
- The process of formation of natural gas takes place over millions of years from decomposing plant and animal material subjected to heat and pressure.
<em>Thus, natural gas cannot be used for the conservation of resources.</em>
Answer: B. increase
Explanation: During an action potential, the potassium level inside the cell decreases, and the sodium level inside the cell increases. Thats is to say there is an outflow of potassium and an inflow of sodium ions.
Action potential usually occurs when an electrical signal disrupts the balance of Na+ and K+ within a cell membrane, briefly depolarizing the concentrations of each.
