📜 Laws of Reflection

1. Angle of incidence = Angle of reflection: \( \angle i = \angle r \)
2. Incident ray, reflected ray & normal lie in the same plane.
Deviation Angle: \( \delta = 180^\circ - 2i \)

🪞 Plane Mirror Image Properties

• Virtual, erect, same size (\( m = +1 \))
• Image distance = Object distance (\( v = -u \))
• Laterally inverted  |  Focal length \( f = \infty \)

🔢 Mirror Formula & Magnification

📋 Sign Convention Rules

• Object distance \( u \): always −ve
• Concave mirror: \( f = -\text{ve} \), \( R = -\text{ve} \)
• Convex mirror: \( f = +\text{ve} \), \( R = +\text{ve} \)

⚡ Snell's Law & Refractive Index

📑 Refraction Through Glass Slab

• Emergent ray parallel to incident ray (\( i = e \))
• Apparent Depth: \( \text{Apparent Depth} = \dfrac{\text{Real Depth}}{n} \)
• Lateral Shift \( \Delta y = t \left(1 - \dfrac{1}{n}\right) \)

🔢 Lens Formula & Magnification

🔍 Lens Image Characteristics

• Convex Lens: Real/Virtual depending on \( u \). Virtual & magnified when \( u < f \).
• Concave Lens: Always virtual, erect & diminished (\( v = -\text{ve} \), \( m < 1 \)).

⚡ Power of a Lens (P)

🔗 Combination of Lenses in Contact