Скачать или смотреть Applied physics || . Chapter 1 Wave Motion and its Applications in english part 2

Applied physics || . Chapter 1 Wave Motion and its Applications in hindiWave Motion (तरंग गति) - Introduction
​Wave motion ek prakar ka disturbance (vishu) hai jo energy ko ek jagah se doosri jagah transfer karta hai bina medium ke particles ko permanently shift kiye.
​Note: Ismein kewal Energy transfer hoti hai, Matter (padarth) nahi.
​2. Types of Waves (तरंगों के प्रकार)
​Mechanical waves (jinhein chalne ke liye medium chahiye) do tarah ki hoti hain:Transverse Waves (अनुप्रस्थ तरंगें)
​Jab medium ke particles wave ke chalne ki disha ke Perpendicular (lambwat) vibrate karte hain.
​Yeh Crests (shring) aur Troughs (gart) ke roop mein aage badhti hain.
​Examples: Light waves, rassi mein utpann tarangein.
​B. Longitudinal Waves (अनुदैर्ध्य तरंगें)
​Jab medium ke particles wave ke chalne ki disha ke Parallel (samaantar) vibrate karte hain.
​Yeh Compressions (sampidan) aur Rarefactions (virlan) ke roop mein aage badhti hain.
​Examples: Sound waves (dhwani tarangein).
​3. General Definitions (मुख्य परिभाषाएं)
​Wave motion ko samajhne ke liye kuch technical terms samajhna zaroori hai:
​Amplitude (आयाम - a): Mean position se maximum displacement ko amplitude kehte hain.
​Time Period (आवर्तकाल - T): Ek complete vibration mein lagne wala samay.
​Frequency (आवृत्ति - n or f): Ek second mein hone wale vibrations ki sankhya. (Unit: Hertz - Hz).
​Wavelength (तरंगदैर्ध्य - \lambda): Do lagatar Crests ya Troughs (ya Compressions/Rarefactions) ke beech ki doori.
​Wave Velocity (तरंग वेग - v): Ek second mein wave dwara tay ki gayi doori.
​Relation between Velocity, Frequency, and Wavelength
​Yeh formula numericals ke liye bahut important hai:Isse Simple Harmonic Motion kehte hain (Jaise pendulum ki gati).
​5. Acoustics of Buildings (भवनों की ध्वनिकी)
​Yeh topic Civil aur Architecture engineering ke liye bahut mehatvapoorn hai.
​A. Reverberation (अनुरणन)
​Jab kisi band kamre mein source band hone ke baad bhi awaaz kuch der tak goonjti rehti hai, toh is phenomenon ko Reverberation kehte hain.
​B. Reverberation Time (अनुरणन काल)
​Woh samay jismein sound ki intensity apni initial value ki 10^{-6} (one-millionth) reh jaati hai.
​C. Sabine’s Formula (सेबिन का सूत्र)
​Reverberation time (T) nikalne ke liye Professor Sabine ne ek formula diy​T = Reverberation Time (seconds)
​V = Volume of the hall (m^3)
​A = Total Absorption (m^2 sabine) = \sum a \cdot s
​Achhe Hall ke liye: Reverberation time na bahut zyada hona chahiye (goonj) aur na bahut kam (dead silence). Standard time lagbhag 1 se 2 seconds hota hai.
​6. Ultrasonic Waves (पराश्रव्य तरंगें)
​Human ear ki sunne ki range 20 Hz se 20,000 Hz hoti hai.
Jo waves 20,000 Hz (20 kHz) se upar hoti hain, unhein Ultrasonics kehte hain.
​Production of Ultrasonic Waves (उत्पादन)
​Inhein normal speakers se paida nahi kiya ja sakta. Iske liye do mukhya methods hain:
​Magnetostriction Method (चुम्बकीय विरूपण): Ferromagnetic rod ko magnetic field mein rakhne par uski length change hoti hai, jisse vibrations paida hote hain.
​Piezoelectric Method (दाब-विद्युत प्रभाव): Quartz crystal par electric field lagane se woh vibrate karta hai aur ultrasonic waves banata hai.
​Applications of Ultrasonics (अनुप्रयोग)
​Yeh exam mein aksar pucha jata hai:
​SONAR: Paani ke neeche objects (jaise submarine) ki dhoondne ke liye.
​Depth of Sea: Samudra ki gehrai napne ke liye.
​Medical Science: Ultrasonography (Ultrasound) mein body ke internal organs ko dekhne ke liye.
​Drilling: Hard materials (jaise diamond) mein ched karne ke liye.
​Cleaning: Watches aur electronic parts ke purze saaf karne ke liye.
​Important Questions for Exam (महत्वपूर्ण प्रश्न)
​Transverse aur Longitudinal waves mein kya antar hai?
​v = n\lambda sambandh sthapit karein.
​Reverberation time kya hai? Sabine ka formula likhein.
​Ultrasonic waves kya hain? Inke upyog likhein.
​Would you like me to solve a numerical problem based on Sabine's formula or the v = n\lambda equation?