There's supposed to be a blank in the statement, where the answer is supposed to be inserted.
The question is supposed to say: "A wave is a disturbance that carries ______ from one place to another through matter or space".
To answer the question, write the word "<em>energy</em>" in the blank.
Answer:
Light comes in different colors like radio, ultra violet, gamma-ray, etc, and they are invisible to the bare eye
Explanation:
5.4 x 1014Hz
wavelength x frequency = the speed of light
The car's velocity is (distance + direction) / (time) =
(75 km-north) / (1.5 hrs) =
(75/1.5) (km-north/hr) = 50 km/hr north.
Answer:
- Direct current is a current in which electrons flow in one direction only
- Alternating current is a current in which the direction of the electron flow reverses periodically - so, half a cycle forward, half a cycle backward
There are several advantages of using alternating currents for the transmission of electricity across a country, over large distances. The main advantages are:
- The voltage of alternating currents can be easily increased/decreased by using transformers. For instance, a transformer is used at the beginning of the transmission line to increase the voltage (electricity is transmitted at high voltage in order to reduce dissipated power), and then another transformer is used before the electricity enters the houses, in order to decrease the voltage. Transformers only work with alternating currents.
- It is easy to interrupt the flow of an alternating current, because its value naturally becomes zero every half a cycle, so this is useful in case the current must be interrupted.
