This is the basic knowledge you need to understand Bohr’s Model of Atom.
1. Atomic Structure & Motion
Why don’t electrons lose energy while orbiting the nucleus?
- You questioned how moving particles don’t lose energy like moving objects do.
Answer: In Bohr’s model, electrons move in fixed orbits (energy levels) without radiating energy due to quantum rules. Energy is only lost or gained when they jump between levels.
Doesn’t movement require continuous energy?
- In classical physics, yes — but in atomic systems, stable orbits exist due to quantization.
- Newton’s laws apply differently at quantum scales.
2. Planetary Motion & Forces
Why don’t planets fall into the sun?
- They are already moving tangentially with inertia; gravity pulls them inward, balancing the motion into orbits.
- Elliptical orbits form due to conservation of angular momentum and the nature of gravitational interaction.
3. Basics of Electromagnetic Waves
What are electric and magnetic fields?
- Electric field: region where a charge feels force.
- Magnetic field: region where a moving charge or magnet feels force.
Are E and B fields attracting each other?
No attraction — they generate each other when changing, but stay perpendicular.
4. Understanding Waves
What is a wave?
- Disturbance that carries energy, not matter.
- You were confused whether particles actually “move in the wave shape”.
- Answer: In most waves, particles vibrate at their place , and the disturbance travels.
What is vibration?
- To-and-fro motion about a mean position.
- Examples: A clock pendulum, air molecules.
5. Restoring Force & Oscillations
Why do particles vibrate?
- Due to restoring force — a force that tries to bring the particle back to equilibrium.
- Think of springs or molecules in air.
6. Electromagnetic Waves Continued
How is EM wave created?
- A changing electric field creates a magnetic field , and vice versa.
- Together they form self-sustaining waves.
What’s their shape & movement?
- Electric field (E): oscillates in one plane (say y-axis),
- Magnetic field (B): oscillates in perpendicular plane (say z-axis),
- Wave propagates in a third, perpendicular direction (say x-axis).
- All 3 directions are mutually perpendicular .
7. Common Confusions
Does EM wave involve particles vibrating?
- No, it’s not particles, it’s fields changing in magnitude and direction.
- But understanding mechanical vibrations helps grasp wave concepts.
Thanks!