Light

Compound Microscope Object lens: Higher powerEye lens: Lower power Position of the object: The object is placed at a position between fo and 2fo. Nature of the image, I1: Real, inverted and magnified Position of the image, I1: The first image, I1 must be placed between the optical center of the eye lens with the eye lens principle focus point, … Read more

Astronomical Telescope Objective lens: Lower powerEye lens: Higher power Position of the object: At infinityNature of the image, I1: Real, inverted and magnified Position of the image, I1: At the principal focus of object lens, fo.Nature of the image, I2: Virtual, inverted and smaller in size. Distance in between the two lens The distance between the object lens and the eye … Read more

Projector Function Bulb Bulb with high brightness is used. The bulb must be placed at the centre of curvature of the concave mirror. Concave mirror The function of the concave mirror is to reflect and focus light that shines on it to the direction of the condenser. This is to increase the brightness of the … Read more

Magnifying Glass The magnifying glass is also known as a simple microscope. A magnifying glass is a single convex lens with short focal length. The image formed is virtual, magnified upright A magnifying glass enlarges the image of an object by increasing the virtual angle at the eye when the object is viewed. Angular magnitude … Read more

The Lens Equation The following is the lens equation that relates the object distance (u), image distance (v) and the focal length.  When using the lens equation to solve the problem, it’s important to note the positive negative sign of u, v and f. The table below gives the conventional symbol and sign for u, … Read more

The image formed by a concave lens always has the same characteristics, namely virtual upright diminish Figure below shows the ray diagram for the formation of image of a concave lens.

Rules in Drawing Ray Diagram for Concave Lens A light ray passes through the optical centre of the lens will not be refracted. A light ray parallel to the principle axis will be refracted away from the principle focus A light ray moving towards the optical centre will be refracted parallel to the principle axis. … Read more

Characteristics of the Image Formed by a Convex Lens As with a curved mirror, the position and size of an image can be found by drawing a ray diagram. Any two of the following three rays are sufficient to fix the position and size of the image. The characteristics, position and size of the image … Read more

Rules for Drawing Ray Diagram for Convex Lenses A light ray passes through the optical centre of the lens will not be refracted. A light ray parallel to the principle axis of the lens will be refracted passes through the principle focus. A light ray passes through principle focus will be refracted parallel to the … Read more