25.1 Surface and Internal Waves
Surface Waves
- Travel along Earth’s surface.
- Types:
- Rayleigh waves → Roll like ocean waves, both vertical & horizontal motion.
- Love waves → Horizontal shear motion, faster than Rayleigh.
Internal Waves (Body Waves)
- Travel inside the Earth.
- P-waves (Primary) → Longitudinal, fastest, travel through solids & liquids.
- S-waves (Secondary) → Transverse, slower, travel only through solids.
Wave Patterns of Gorkha Earthquake 2015
- Epicenter → Barpak, Gorkha.
- First to arrive: P-waves
- Followed by: S-waves
- Last: Surface waves (Rayleigh & Love → cause most destruction)
25.2 Gravitational Wave, Nanotechnology & Higgs Boson
Gravitational Waves
- Ripples in space-time caused by massive accelerating objects (e.g., black hole collisions).
- Predicted by Einstein’s General Relativity (1916).
- Detected first in 2015 by LIGO.
Nanotechnology
- Study & manipulation of matter at 1–100 nm scale.
- Applications: Medicine, electronics, material science, water purification.
Higgs Boson
- Particle responsible for giving mass to other particles.
- Predicted by Peter Higgs (1964).
- Discovered at CERN (LHC) in 2012.
Short Questions and Answers in Short
Q1. What are Rayleigh waves?
Ans: Surface waves with rolling motion, vertical & horizontal.
Q2. What are Love waves?
Ans: Surface waves with horizontal shear motion.
Q3. Difference between P-wave and S-wave?
Ans: P-wave: longitudinal, fastest, solids & liquids.
S-wave: transverse, slower, only solids.
Q4. Which waves caused maximum damage in Gorkha earthquake 2015?
Ans: Surface waves (Rayleigh & Love).
Q5. What are gravitational waves?
Ans: Ripples in space-time caused by massive objects accelerating.
Q6. When were gravitational waves first detected?
Ans: 2015 by LIGO.
Q7. Define nanotechnology.
Ans: Manipulation of matter at 1–100 nm scale.
Q8. Applications of nanotechnology?
Ans: Medicine, electronics, material science, water purification.
Q9. What is Higgs boson?
Ans: Particle that gives mass to other particles.
Q10. When and where was Higgs boson discovered?
Ans: 2012 at CERN (LHC).
✅ Quick Revision
