Define frequency, time period, and wavelength
Scenario
Agar koi heart monitor ko dekhe, toh usme beeps ek fix time baad aati hain. Aur har wave ki apni ek lambai hoti hai.
Sound waves ki lambai aur timing ko hum kin terms mein measure karte hain?
Mental model
Wavelength ek step ki lambai hai, Time period ek step lene ka time hai, aur Frequency ek second mein kitne steps liye gaye hain, wo hai.
Jab sound wave chalti hai, toh do lagataar compressions ke beech ki doori ko Wavelength kehte hain. Ek cycle poori hone ka time Time Period hai, aur ek second mein aisi kitni cycles aayi, wo Frequency hai.
Explanation
Sound wave ko describe karne ke liye hum 3 main terms ka use karte hain: **Wavelength**, **Frequency**, aur **Time Period**.
**Wavelength** (`\lambda`): Ek wave ka ek poora cycle jitni distance mein complete hota hai, use wavelength kehte hain. Longitudinal wave mein, do consecutive compressions ya do consecutive rarefactions ke beech ke distance ko wavelength kehte hain. Iski SI unit meter (`m`) hai.
**Frequency** (`\nu`): Ek second mein kitne complete oscillations ya cycles ban rahe hain, use frequency kehte hain. Agar koi cheez `1` second mein `50` baar vibrate karti hai, toh uski frequency `50 Hz` hogi. Iski SI unit Hertz (`Hz`) hai.
**Time Period** (`T`): Ek complete oscillation poora karne ke liye wave kitna time leti hai, use time period kehte hain. Iski SI unit second (`s`) hai.
Frequency aur time period aapas mein closely related hain. Formula hai: `T = 1 / \nu` (ya `\nu = 1 / T`). Yaani frequency jitni zyada hogi, time period utna hi kam hoga.
Worked example
Problem: A sound wave has a frequency of `200 Hz`. What is the time period of this wave?
- Hamein frequency di gayi hai, aur time period nikalna hai. Hum reciprocal formula use karenge.
- Value put karenge aur solve karenge.
Answer: `0.005 s`
Problem: If the time taken for one complete oscillation is `0.02 s`, what is its frequency?
- Is baar time period diya gaya hai, toh hum frequency nikalne ke liye same formula ka reverse order use karenge.
- Time ki value daal kar calculate karenge.
Answer: `50 Hz`
Key points
- Wavelength (λ): The distance between two consecutive compressions or rarefactions. SI unit is meter (`m`).
- Frequency (ν): The number of oscillations per second. SI unit is Hertz (`Hz`).
- Time Period (T): The time taken for one complete oscillation. SI unit is second (`s`).
- Relationship: Frequency and time period are reciprocals: `T = 1 / \nu`
Common mistakes
- Mixing up wavelength and amplitude: Wavelength do compressions ke beech ki horizontal distance hoti hai, jabki amplitude mean position se maximum vertical displacement hota hai. Inhe mix mat karo.
Recall questions
- What is the SI unit of frequency?
- What is the relation between frequency and time period?
- What is the SI unit of wavelength?
Questions & answers
What are wavelength, frequency, time period and amplitude of a sound wave?
Wavelength is the distance between two consecutive compressions. Frequency is the number of oscillations per second. Time period is the time taken for one complete oscillation.
Approach: Define each term with its SI unit.
Define time period of a sound wave.
The time taken for one complete oscillation in the density of the medium is called the time period.
Approach: State the standard definition.
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