Question

What is the time taken by a pendulum to complete one oscillation called?
A. Amplitude
B. Time period
C. Frequency
D. Mean position

Answer 1

Hint: One oscillation is defined as movement of the pendulum to its maximum height from its mean position. Period and time have little difference. Time cannot be fixed but periods will always be fixed quantities.

Complete step-by-step answer:
Let's understand this by taking an example. Take one string and bob/stone. Tie string to a bob. Hold it at a certain height. With constant force, swing it. You will observe that Bob is going at a certain distance either on the right side or left side and then come back to the position where you have stated. And again it is covering some distance rather left side or right side and again comes back to starting position also known as means position. The mean position is nothing but a point where you have started it to oscillate. So this kind of behavior is nothing but oscillation.
So Pendulum is the body having bob suspended by string so that it can swing. When it gets released a restoring force is acted on it which is responsible to oscillate bob or pendulum.
We know that in motion that repeats itself at a regular interval of time is called period motion or time period. The smallest interval of the time after which motion repeats itself is called its period. Letters denote the period T. SI unit of time period is the second.
The reciprocal of T gives the number of repetition that occurs per unit time. This quantity is called frequency of the periodic motion. It is represented by this symbol. The relationship between is $\nu$and T is
$\nu =\dfrac{1}{T}$
The SI unit of frequency is the second inverse. After the discovery of radio waves, a special name has been given to the unit of frequency it is called Hertz.

Note: time is a reciprocal of frequency. Time depends on frequency. SI unit of time period is second. Dimension of the second is$[T]$. You can relate the time period with the clock or wristwatch. It has the same time period.