wavelength and frequency?why?

Question

can you explain this to me pls.
Velocity = 2450 MHz X 0.122 m

Velocity = 2.99 X 10^8 m/s

(is there any convesion done to get 2.99X10^8???)

Answer 1

Yes, there is a conversion. MHz is 1 x 10^6 Hz. So you have v = (2450 MHz)(0.122 m) = (2450 x 10^6 Hz)(0.122 m) = 2.989 x 10^8 m/s, because 1 Hz is the same thing as 1 s^-1.

Answer 2

no: 2450*0.122=298...

Units are just as important as the numbers preceding the unit symbol. Units allow us to understand what you are talking about.
To a VELOCITY is associated some unit of DISTANCE over some unit of TIME. Just as "miles" or "meter m" are units of distance, "Hertz Hz" is a unit of FREQUENCY. Frequency is defined as the number of times something happens in a unit of time (in a second, an hour or whatever): e.g. the number of times you can cross a bridge in a minute. So FREQUENCY is a count per unit of time. The Hz is a count per second (/s)

You see now that METERS x HERTZ is the same as METERS/SECONDS ?
now the "M" in front of Hz means 10^6 Hz

Summed up:
v= (2450 x 0.122) MHz x m = 298 x 10^6 m/s = 2.98 x 10^8 m/s

Answer 3

Ok, to solve this problem you need to first convert from MHz to Hz.

First we'll use dimensional analysis to convert the units we'll be needing to get to.

2450MHz x (1,000 KHz / 1 MHz) x (1,000 Hz / 1 KHz) = 2450 x 1000 x 1000 = 2450 x 1,000,000 => 2.450 x 10^9 Hz

Now 1 Hz = s^-1 or /s

Now to find the velocity we simply plug our knowns into the equation of V = DT

V = .122m * 2.450 x 10^9 /s

V = 2.99 x 10^8 m/s Final anwer.

Answer 4

This of course is only for electromagnetic waves like light or radio waves in a vacuum.

If you look at the units velocity is metres per second.

Hz is a cycle per second and the wavelength is distance.

So Hz times distance is the same units as velocity.

Answer 5

It's not a "conversion", it is the direct answer. You need to learn how to use units, there are some good examples above. One extra thing to point out is that the M is simply a number, it can be separated from the unit for ease in calculations; e.g.

2450MHz(0.122m) = 298.9(M)(1/s)(m) = 298.9M(m/s) which gives the result in megameters per second if you wish.