AP Board 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces

Students can go through AP State Board 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces to understand and remember the concept easily.

AP State Board Syllabus 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces

→ The lens is an optical system with two refracting surfaces.

→ The lens which is thicker at its centre than edges is called a convex (or) converging lens.

→ The lens which is thicker at its edges than the centre is called a concave (or) diverging lens.

→ The lemon in the water of the glass tumbler appears bigger than its actual size when viewed from the sides of the tumbler due to refraction.

→ The relation between refractive indices of media, object distance, image distance and radius of curvature is given by
\(\frac{n_{2}}{v}-\frac{n_{1}}{u}=\frac{\left(n_{2}-n_{1}\right)}{R}\)

→ In the case of plane surfaces, R & f are infinity. Power is equal to zero.
∴ \(\frac{n_{2}}{v}=\frac{n_{1}}{u}\)

→ Each curved surface of a lens is part of a sphere.

→ The centre of the sphere which contains the part of the curved surface is called the centre of curvature.

→ The midpoint of the lens is called a pole (or) optical centre.

→ The point from which rays seem emanating is called focal point or focus (F). (or) The point where rays converge is called the focal point of focus.

AP Board Solutions AP Board 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces

→ Every lens has two focal points.

→ The distance between the focal point and pole is called focal length which is denoted by f.

→ The line that joins the centre of curvature and the pole is called the principal axis.

→ The distance between the centre of curvature and pole is called the radius of curvature (R).

→ Any ray passing through the principal axis is un-deviated.

→ Any ray passing through the pole is also un-deviated.

→ The rays passing parallel to the principal axis converge at focus or diverge from focus.

→ The ray passing through the focus of the convex lens will take a path parallel to the principal axis after refraction.

→ When parallel rays fall on the lens making a certain angle with the principal axis the rays converge at a point or appear to diverge from a point lying on a focal plane.

→ If the size of the image is larger than that of an object, it is called a magnified image.

→ Lens formula is \(\frac{1}{v}-\frac{1}{u}=\frac{1}{f}\)
v = image distance
u = object distance
f = focal length.

→ Lens maker formula is \(\frac{1}{f}\) = (n -1)\(\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)\)
n is the absolute refractive index
R1 R2 are radii of curvature.

→ Lens: A lens is formed when a transparent material is bounded by two spherical surfaces.

→ Focal Length (f) The distance between the focal point and optic centre (pole) is called the focal length of the lens. It is denoted by f.

→ Focus (F): The point of converging lar) the point from which rays seem emanating is called focal point or focus.

→ The optic centre or Pole (P): The midpoint of a thin lens is called a pole or optical centre.

→ Principal axis: The line joining the centre of two curved surfaces is called the principal axis
(or)
The line joining the centre of curvatures and the pole.

AP Board Solutions AP Board 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces

→ The radius of curvature (R): The distance between the centre of curvature and the optic centre is called the radius of curvature.

→ Centre of curvature (C): The centre of the sphere which contains the part of the curved surface is called the centre of curvature.

→ Focal plane: A plane that is perpendicular to the principal axis at the focus is called the focal plane.

→ Beam: A number of rays combined together are called a beam.

→ Ray: The straight-line path along which the light travels, in a homogeneous medium, is called a ray.

→ Convergent beam: When a group of light rays fall on a convex lens after refraction meets at a point is called a convergent beam.

→ Divergent beam: When a group of light rays fall on a concave lens after refraction move away from a point is called a divergent beam.

→ Parallel beam: When a group of light rays parallel to each other is called a parallel beam.

→ Real image: The image formed on the screen is called a real image.

→ Virtual image: The ¡mage which cannot be formed on the screen is called a virtual image.

→ Aperture: The effective width of a lens through which refraction takes place ¡s called the aperture.

→ Magnifying glass: A glass, which enlarges an object.

→ Biconvex or Double convex lens: A lens that may have two spherical surfaces bulging outwards is called a double convex lens.

AP Board Solutions AP Board 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces

→ Biconcave or Double concave Pens: It is bounded by two spherical surfaces curved inward.

→ Lens formula: \(\frac{1}{\mathrm{v}}-\frac{1}{\mathrm{u}}=\frac{1}{\mathrm{f}}\)
v = image distance
u = object distance
f = focal length of tens

→ Lens maker’s formula: \(\frac{1}{f}\) = (n -1)\(\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)\)
n = Absolute refractive index
R1 = Radius of curvature of the first surface
R2 = Radius of curvature of the second surface

→ Enlarged image (Magnified image): If the size of the image is greater than that of an object, it is called an enlarged (or) magnified image.

→ Diminished image: If the size of the image is less than that of an object, it Is called a diminished Image.

→ Object distance (u) : Distance between object and lens (optic centre).

→ Image distance (v) : Distance between image and lens (optic centre).
AP Board 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces Notes 1

AP Board Solutions AP Board 10th Class Physical Science Notes Chapter 4 Refraction of Light at Curved Surfaces

→ Sir David Brewster (11 Dec. 1781 – 10 Feb. 1868):

  • Sir David Brewster was a Scottish physicist, mathematician, astronomer, inventor, writer, historian of science.
  • Most noted for his contributions to the field of optics.
  • He studied the double refraction by compression and discovered the photoelastic effect.
  • William Whewell dubbed him the ‘Father of modern experimental optics and ‘The Johannes Kepler of optics’.
  • He Is well recognized by the Inventor of Kaleidoscope and stereoscope.