PHYSICS CLASS 10 NOTES
Chapter: Light – Reflection and Refraction
Compiled by: Samar Sharma
PART 1: REFLECTION OF LIGHT
1. Basics of Light & Reflection
Light: A form of electromagnetic radiation that enables us to see objects. It exhibits a dual nature (wave and
particle) and travels in a straight line in a homogenous medium (known as the rectilinear propagation of light).
Reflection of Light: The phenomenon of bouncing back of light rays into the same medium when they strike
a highly polished or smooth surface like a mirror.
Laws of Reflection:
1. The angle of incidence is always equal to the angle of reflection (∠i = ∠r).
2. The incident ray, the normal at the point of incidence, and the reflected ray all lie in the same plane.
2. Spherical Mirrors
Mirrors whose reflecting surfaces are curved or form a part of a hollow sphere are called spherical mirrors.
• Concave Mirror (Converging): A spherical mirror whose reflecting surface is curved inwards (faces
towards the center of the sphere).
• Convex Mirror (Diverging): A spherical mirror whose reflecting surface is curved outwards (faces away
from the center of the sphere).
Important Terms Related to Spherical Mirrors:
• Pole (P): The geometric center of the reflecting spherical surface.
• Center of Curvature (C): The center of the hollow glass sphere of which the mirror forms a part.
• Radius of Curvature (R): The distance between the Pole and the Center of Curvature (R = PC).
• Principal Axis: The straight line passing through the pole and the center of curvature of the mirror.
• Principal Focus (F): The point on the principal axis where light rays parallel to the principal axis actually
converge (in a concave mirror) or appear to diverge from (in a convex mirror) after reflection.
• Focal Length (f): The distance between the Pole and the Principal Focus (f = PF).
Relationship between Radius of Curvature and Focal Length:
f = R / 2 or R = 2f
Class 10 Physics • Light Notes • Samar Sharma Page 1 of 4
Chapter: Light – Reflection and Refraction
Compiled by: Samar Sharma
PART 1: REFLECTION OF LIGHT
1. Basics of Light & Reflection
Light: A form of electromagnetic radiation that enables us to see objects. It exhibits a dual nature (wave and
particle) and travels in a straight line in a homogenous medium (known as the rectilinear propagation of light).
Reflection of Light: The phenomenon of bouncing back of light rays into the same medium when they strike
a highly polished or smooth surface like a mirror.
Laws of Reflection:
1. The angle of incidence is always equal to the angle of reflection (∠i = ∠r).
2. The incident ray, the normal at the point of incidence, and the reflected ray all lie in the same plane.
2. Spherical Mirrors
Mirrors whose reflecting surfaces are curved or form a part of a hollow sphere are called spherical mirrors.
• Concave Mirror (Converging): A spherical mirror whose reflecting surface is curved inwards (faces
towards the center of the sphere).
• Convex Mirror (Diverging): A spherical mirror whose reflecting surface is curved outwards (faces away
from the center of the sphere).
Important Terms Related to Spherical Mirrors:
• Pole (P): The geometric center of the reflecting spherical surface.
• Center of Curvature (C): The center of the hollow glass sphere of which the mirror forms a part.
• Radius of Curvature (R): The distance between the Pole and the Center of Curvature (R = PC).
• Principal Axis: The straight line passing through the pole and the center of curvature of the mirror.
• Principal Focus (F): The point on the principal axis where light rays parallel to the principal axis actually
converge (in a concave mirror) or appear to diverge from (in a convex mirror) after reflection.
• Focal Length (f): The distance between the Pole and the Principal Focus (f = PF).
Relationship between Radius of Curvature and Focal Length:
f = R / 2 or R = 2f
Class 10 Physics • Light Notes • Samar Sharma Page 1 of 4
