frequecy and period have an indirect relationship
F=1/4s
=.25 Hertz
1/40 = 0.025 Hertz
Frequency = 1 / (period) = 1/.4 = 2.5 Hz
f = 1/t = 1/0.025 = 40 Hz
The period of a simple pendulum of length 20cm took 120 seconds to complete 40 oscillation is 0.9.
It seems you are talking about radio waves. The wavelength (40 m) multiplied by the frequency (7 million / second) must equal the speed of light (300 million meters/second). It seems that in this example numbers, either the wavelength or the frequency, or both, are not expressed with a great accuracy. For example, if 40 meters is exact, the frequency would be close to 7.5 MHz.
1/40 = 0.025 Hertz
Frequency = 1 / (period) = 1/.4 = 2.5 Hz
f = 1/t = 1/0.025 = 40 Hz
It is 5 Hz.
The speed of a wave is equal to the product of wavelength x frequency. Just convert everything to standard units (wavelength to meters, frequency to hertz), multiply both, and you'll get the result, also in standard units (meters / second).
1 pulse every 40 microseconds is equal to a frequency of 25,000 hertz
12 minutes and 40 seconds
40 Hz
Divide the speed by the wavelength.
The period of a simple pendulum of length 20cm took 120 seconds to complete 40 oscillation is 0.9.
First of all there is no definition of retangular wave. Maybe your retangular is my square wave. and the answer is inconclusive unless you specify the 40% level.
10*4 = 40 metres per second