Answer:
C. The number of positive and negative charges can be the same.
Explanation:
Answer:
1) f= 8.6 GHz
2) t= 0.2 ms
Explanation:
1)
- Since microwaves are electromagnetic waves, they move at the same speed as the light in vacuum, i.e. 3*10⁸ m/s.
- There exists a fixed relationship between the frequency (f) , the wavelength (λ) and the propagation speed in any wave, as follows:

- Replacing by the givens, and solving for f, we get:

⇒ f = 8.6 Ghz (with two significative figures)
2)
- Assuming that the microwaves travel at a constant speed in a straight line (behaving like rays) , we can apply the definition of average velocity, as follows:
where v= c= speed of light in vacuum = 3*10⁸ m/s
d= distance between mountaintops = 52 km = 52*10³ m

⇒ t = 0.2 ms (with two significative figures)
Answer: A thin membrane.
Explanation:
When a sound signal is allowed to pass through the voice coil suspended between permanent magnet, magnetic field will be induced which will cause vibration in the diaphragm - a thin membrane causing disturbance of air in the surrounding of membranes which eventually produce sound waves.
Therefore, we can conclude that a thin membrane of the loud speaker produces sound waves