Answer:
Electromagnetic waves
Explanation:
Electromagnetic waves are waves that consist of oscillating electric and magnetic fields, that oscillate perpendicularly to each other and perpendicularly to the direction of propagation of the wave (for such a reason, these waves are also called transverse waves).
Electromagnetic waves always travel in a vacuum at the same speed, called speed of light:
and they are classified into 7 different types, according to their frequency. From lowest to highest frequency, we have:
Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays
Therefore, gamma rays, x-rays, visible light and radio waves are all types of electromagnetic waves with different frequencies.
Answer:
A metalloid is used because it is a semiconductor and can become more conductive when more light shines on it
Explanation:
The material used in a solar panel is a metalloid. It can often become conductive when more light shines on it.
Metalloids have properties that straddles between those of metals and non-metals.
In essence, they can be conductive or not under certain conditions.
The most important property they exhibit is that they can become more conductive when more light shines on them. This way more electrons are produced.
1. a. longitudinal waves.
There are two types of waves:
- Transverse waves: in transverse waves, the oscillations of the wave occur in a direction perpendicular to the direction of propagation of the wave
- Longitudinal waves: in longitudinal waves, the oscillations of the waves occur parallel to the direction in which the waves are travelling.
So, these types of waves are called longitudinal waves.
2. d. a medium
There are two types of waves:
- Electromagnetic waves: these waves are produced by the oscillations of electric and magnetic field, and they can travel both in a medium and also in a vacuum (they do not need a medium to propagate)
- Mechanical waves: these waves are produced by the oscillations of the particles in a medium, so they need a medium to propagate - therefore, the correct choice is d. a medium
3. a. AM/FM radio
Analogue signals consist of continuous signals, which vary in a continuous range of values. On the contrary, digital signals consist of discrete signals, which can assume only some discrete values. For AM and FM radios, signals are transmitted by using analogue signals.
