09- Lens and Its Types | Convex & Concave Lens Explained |Ray Optics | Satish Goyal physics classes

In this video, we begin an important topic of Ray Optics – Lens and Its Types, which forms the foundation for many numerical problems and conceptual questions in Class 10, Class 11, and Class 12 Physics. This lecture is extremely useful for students preparing for CBSE Board Exams, JEE Main, JEE Advanced, NEET, Olympiads, and other competitive examinations.
A lens is a transparent optical medium bounded by two surfaces, at least one of which is spherical. Lenses play a crucial role in optical instruments such as microscopes, telescopes, cameras, spectacles, and projectors. Understanding the concept of lenses is essential before moving on to advanced topics like image formation, ray diagrams, lens formula, magnification, and optical instruments.
📘 In this lecture, the following topics are explained clearly and step-by-step:
• What is a Lens?
• Definition of Lens
• Optical Centre of a Lens
• Principal Axis of a Lens
• Types of Lenses
• Convex Lens (Converging Lens)
• Concave Lens (Diverging Lens)
• Shapes of Convex Lens
• Shapes of Concave Lens
• Basic behavior of light through lenses
• Difference between convex and concave lenses
• Uses of convex and concave lenses in daily life
• Importance of lenses in physics and technology
A convex lens is thicker at the center and thinner at the edges. It converges parallel rays of light to a point known as the principal focus. Convex lenses are widely used in magnifying glasses, microscopes, cameras, human eyes, and projectors.
A concave lens is thinner at the center and thicker at the edges. It diverges parallel rays of light and always forms a virtual, erect, and diminished image. Concave lenses are commonly used in spectacles for myopia (short-sightedness) and peepholes.
This lecture focuses on conceptual clarity, helping students visualize how light behaves when it passes through different types of lenses. Special attention is given to board-exam definitions, NEET/JEE conceptual points, and common mistakes made by students.
🎯 Who should watch this video?
✔ Class 10 students building optics basics
✔ Class 11 & 12 students studying Ray Optics
✔ JEE Main & Advanced aspirants
✔ NEET aspirants
✔ Olympiad and NTSE students
✔ Foundation course students
This video is part of the Complete Ray Optics Physics Course, where upcoming lectures will include:
✔ Ray Diagrams for Convex and Concave Lenses
✔ Image Formation in Different Positions
✔ Lens Formula Derivation
✔ Magnification
✔ Power of a Lens
✔ Numerical Problems (Board + Competitive level)
📍 About Our Institute
Satish Goyal Physics Classes
📌 Location: Kalkaji, New Delhi
🎓 Coaching for CBSE | JEE Main | JEE Advanced | NEET | Olympiad Physics
🌐 Website: www.satishgoyalphysics.com
📞 Contact: 9711289192
📌 Small batch size | Concept-based teaching | Personal attention
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