The four theories of Light

• Newton’s corpuscular theory.
• Huygen’s wave theory.
• Maxwell’s electro magnetic wave theory.
• Planck’s quantum theory.

So light behaves as a wave and as a particle, depending on the circumstances and the effect being observed. This concept is now known as wave-particle duality. Einstein won the 1921 Nobel Prize in Physics “for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect”.

There are three measurable properties of wave motion: amplitude, wavelength, and frequency. A definitive experiment was Young’s double slit experiment, which demonstrated that light shined at two slits in a screen show an interference pattern characteristic of waves of light, rather than particles.

Basic Theory Light is a form of radiant energy that travels in waves made up of vibrating electric and magnetic fields. These waves have both a frequency and a length, the values of which distinguish light from other forms of energy on the electromagnetic spectrum.

The First Basic Principle of Light ‘Light is a form of energy’ When light reaches a surface, it can be absorbed and transformed into other types of energy.

Properties of light

• Reflection of light.
• Refraction of light.
• Diffraction of light.
• Interference of light.
• Polarization of light.
• Dispersion of light.
• Scattering of light.

10 properties of light

• Properties of Light.
• Properties of Light • • • • • • • • • Effects of Materials on Light Reflection Refraction Dispersion Total Internal Reflection Interference Diffraction Scattering of Light Polarization.

• Science Grade 4.
• Light.
• Optical Devices.
• Sources of Light.
• Light Radiates from a Source.
• Objects that Absorb, Transmit, and/or Reflect Light.
• Bending Light.
• Dispersion of Light.

• Introduction. Light is a form of energy which helps us in seeing objects.
• Sources of Light. luminous.
• Transparent/Translucent/Opaque. transparent.
• Formation of shadows.
• A Pin-Hole Camera.
• Natural Pin-hole Camera.
• Rectilinear Propagation of Light.
• Mirror.

Shadow: An area of darkness formed by an opaque object obstructing light is called a shadow. Objects can be transparent, translucent, or opaque, depending on how much light can pass through them. A shadow is formed when an opaque object blocks the light falling on it.

In a pinhole camera, image formed is inverted because the object is between radius of curvature and focus. What is the path of light? Answer: Straight line.

The light traveling in any one direction in a straight line is called a ray of light. A group of light rays given out from a source is called a beam of light.

Image is formed by the reflection of light rays by an object. Image has the colour of the object. Shadow is formed by the obstruction of light by an opaque object. Shadow is always black.

Hint: Umbra is complete shadow and penumbra is partial shadow. These are the words generally related to eclipse. Students must have a brief knowledge of the formation of solar and lunar eclipses. Complete step by step solution: ”Umbra” is similarly defined as shade while penumbra means partial shade.

Note: When light is obstructed by an opaque object then shadow is formed while the image is the reflection of light rays by any object….Write a few differences between a shadow and an image.

Image	Shadow
3. Image contains colour, structure etc. of the object.	Shadow does not give any information about the object as it is colourless.

Shadow is, as you know pretty well, is that dark portion formed when an opaque object obstruct the light rays from a source while image is the object’s resemblence form by the intersection of the light ray either by direct(which will form real image) or indirect(virtual image)….

A shadow is a dark (real image) area where light from a light source is blocked by an opaque object. It occupies all of the three-dimensional volume behind an object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, or a reverse projection of the object blocking the light.

Simply speaking, a shadow is an absence of light. If light cannot get through an object, the surface on the other side of that object (for example, the ground or a wall) will have less light reaching it. A shadow is not a reflection, even though it is often the same shape as the object.

The light that hits the object is reflected off the front surface and redirected to another part of the room. A silvery bowl creates a shadow on the wall by reflecting away the light that hits its front surface. Refraction. As a result, the beam will have a dark spot; a shadow.

The bending of light as it passes from one medium to another is called refraction. The angle and wavelength at which the light enters a substance and the density of that substance determine how much the light is refracted.

When light falls on an object, some of the light gets reflected. The reflected light comes to our eyes and we are able to see an object. Luminous Object: An object which produces light is called a luminous object, e.g. sun, bulb, etc.

The non-luminous objects can be seen only when the light coming from a luminous object falls on them. This light is reflected by non-luminous objects in all directions. When this reflected light enters our eyes, we can see the non-luminous objects. It does not give its own light.

The position of the sun affects the size of a shadow. A person or object blocks more light when the sun is low in the sky. More blocked light makes shadows longer. The sky turns dark when your part of Earth spins away from the sun.

Shadows are important historically, for they provided early evidence that light travels in straight lines. Because shadows reveal much about an object’s extension in space, they are often used to heighten the illusion of depth in a painting.

Shadows are formed because light travels in straight lines. Shadows are formed when an opaque object or material is placed in the path of rays of light. The opaque material does not let the light pass through it. The light rays that go past the edges of the material make an outline for the shadow.

When you block two lights, you see a shadow of the third color—for example, block the red and green lights and you get a blue shadow. If you block only one of the lights, you get a shadow whose color is a mixture of the other two.

A shadow is an area where direct light from a relatively small source is blocked by some opaque object. If the source is genuinely the only light around, the shadow will be absolutely black, and will have no colour. A shadow is an area where direct light from a relatively small source is blocked by some opaque object.

Light travels in straight lines. When light reaches an object, it can travel through the object if the object is transparent. Shadows are produced when light hits an opaque object which prevents the light beams from passing through. When an object blocks the light’s path, then darkness appears on the other side.

Shadows are Blue Meaning that blue is the general color for most shadows. Most of us think of shadows as being black, however black is a neutral color. The hue of shadow is in fact blue.