The whole definition of frequency is: <em>How often something happens. </em>
Especially referring to something that happens over and over and over and over.
One example is Choice-C: How often the particles of a medium vibrate.
"Frequency" comes from the word "frequent". That means "often", and "frequency" just means "often-ness" ... HOW often the thing happens.
Some other examples:
Frequency of jump-roping . . . maybe 60 per minute .
Frequency of rain . . . maybe 5 per month .
Frequency of an AM radio station . . . maybe 1 million waves per second.
(If it's something <u><em>per second</em></u>, then we call it "Hertz". That's not for the car rental company. It's for Heinrich Hertz, the German Physicist who was the first one to prove that electromagnetic waves exist. He sent radio waves all the way ACROSS HIS LABORATORY and detected them at the other side ( ! ), in 1887.)
Frequency of the wiggles in the sound wave coming out of a trumpet playing the note ' A ' . . . 440 Hertz.
Frequency of sunrise and the Chicago Tribune newspaper . . . 1 per day
Frequency of the cycle of Moon phases and an average human woman's ovulation cycle: 1 per 29.531 days, 1 per ~28 days .
Answer: True
Explanation:
Atomic number is defined as the number of protons or the number of electrons that are present in an electrically neutral atom.
Atomic number = Number of protons = number of electrons = 2
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.
The electronic configuration will be 
As its duplet is already complete and it has noble gas configuration , it is stable with 2 valence electrons.
Answer:
For a body moving at a uniform velocity you can calculate the speed by dividing the distance traveled by the amount of time it took, for example one mile in 1/2 hour would give you 2 miles per hour. If the velocity is non-uniform all you can say is what the average speed is.
Answer:
The sound level will be 1.870 dB louder.
Explanation:
Given that,
Power = 130 W
Power = 200 W
We need to calculate the sound level
Using formula of sound level

For one amplifier,
...(I)
For other amplifier,
...(II)
For difference in dB levels




Hence, The sound level will be 1.870 dB louder.