period

(noun)

The duration of one cycle in a repeating event.

Related Terms

Examples of period in the following topics:

  • The Periodic Table of Elements

    • The periodic table is a tabular display of the chemical elements.
    • Groups usually have more significant periodic trends than do periods and blocks, which are explained below.
    • A period is a horizontal row in the periodic table.
    • Here is the complete periodic table with atomic numbers, groups, and periods.
    • Explain how properties of elements vary within groups and across periods in the periodic table

  • The Periodic Table

    • The rows of the table are called periods.
    • Isotopes are never separated in the periodic table.
    • The standard form of the periodic table, where the colors represent different categories of elements
    • Mendeleev's 1869 periodic table presents the periods vertically and the groups horizontally.
    • Dmitri Mendeleev is known for publishing a widely recognized periodic table.

  • Period and Frequency

    • The period is the duration of one cycle in a repeating event, while the frequency is the number of cycles per unit time.
    • The period is one 200th of a second, T=1/f=(1/200) s=0.005 s.
    • The usual physics terminology for motion that repeats itself over and over is periodic motion, and the time required for one repetition is called the period, often expressed as the letter T.
    • Note that period and frequency are reciprocals of each other .
    • The SI unit for period is the second.

  • The Simple Pendulum

    • Example:Measuring Acceleration due to Gravity: The Period of a Pendulum.What is the acceleration due to gravity in a region where a simple pendulum having a length 75.000 cm has a period of 1.7357 sStrategy: We are asked to find g given the period T and the length L of a pendulum.
    • This is why length and period are given to five digits in this example.
    • Using this equation, we can find the period of a pendulum for amplitudes less than about 15º.
    • or the period of a simple pendulum.
    • The period is completely independent of other factors, such as mass.

  • Examples

    • It's because we've assume the function is periodic on the interval $[-1,1]$.
    • The {\it periodic extension} of $f(x) = x$ must therefore have a sort of sawtooth appearance.
    • In other words any non-periodic function defined on a finite interval can be used to generate a periodic function just by cloning the function over and over again.
    • Figure~\ref{sawtooth} shows the periodic extension of the function $f(x) = x$ relative to the interval $[0,1]$.
    • What would the periodic extension of $f(x) = x$ look like relative to the interval $[-.5,.5]$?

  • The Physical Pendulum

    • The period of a physical pendulum depends upon its moment of inertia about its pivot point and the distance from its center of mass.
    • In this case, the pendulum's period depends on its moment of inertia around the pivot point .
    • This is of the same form as the conventional simple pendulum and this gives a period of:
    • The important thing to note about this relation is that the period is still independent of the mass of the rigid body.
    • This, in turn, will change the period.

  • The Speed of a Wave on a String

    • The speed of a wave on a string can be found by multiplying the wavelength by the frequency or by dividing the wavelength by the period.
    • Refer to Figure 2 for a visual representation of these terms.The amplitude is the maximum displacement of a particle from its equilibrium position.Wavelength, usually denoted with a lambda (λ) and measured in meters, is the distance from either one peak to the next peak, or one trough to the next trough.Period, usually denoted as T and measured in seconds, is the time it takes for two successive peaks, or one wavelength, to pass through a fixed point.Frequency, f, is the number of wavelengths that pass through a given point in 1 second.
    • Frequency is measured by taking the reciprocal of a period: $f=\frac1T$
    • In waves, this is found by dividing the wavelength by the period:$v=\frac{\lambda}T$We can take the inverse proportionality to period and frequency and apply it to this situation:$v=\frac{\lambda}T\\ v={\lambda}\frac1T\\ v={\lambda}f$

  • Kepler's Third Law

    • The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit .
    • where P is the orbital period of the planet and a is the semi-major axis of the orbit (see ).
    • Now, to get at Kepler's third law, we must get the period P into the equation.
    • By definition, period P is the time for one complete orbit.
    • Now the average speed v is the circumference divided by the period—that is,

  • Motion with Constant Acceleration

    • Constant acceleration occurs when an object's velocity changes by an equal amount in every equal time period.
    • An object experiencing constant acceleration has a velocity that increases or decreases by an equal amount for any constant period of time.
    • When it is not, we can either consider it in separate parts of constant acceleration or use an average acceleration over a period of time.

  • Period of a Mass on a Spring

    • The period T can be calculated knowing only the mass, m, and the force constant, k:
    • This will lengthen the oscillation period and decrease the frequency.
    • This reduces the period and increases the frequency.
    • The stiffer the spring is, the smaller the period T.
    • The greater the mass of the object is, the greater the period T.