Optics is still a highly significant topic for all JEE and other Engineering entrance test candidates. In the JEE prior year examinations, Ray Optics and Wave Optics combined account for more than 10% of the points in the Physics portion. The themes for the class 12th board examinations are clearly defined. So, familiarise yourself with the ideas and practise numerical problems that use ray diagrams. The following are the key ideas in the Physics Optics portion:
- Spherical lens numerical
- Ray Diagrams
- Snell’s Law
- Image Formation by Spherical Mirrors
- Reflecting Telescope
- Huygens Principle
- Polarization: Brewster’s Law
- Lens Formula
- Young’s Double Silt Experiment
What section in ray & wave optics should be studied first? Both chapters are equally significant and may be studied individually. It’s entirely up to you to decide where to begin. However, it is customary to learn ray optics first. You should also pay attention since several words from ray optics may be utilised in wave optics. Let’s have a little look at both ray and wave optics.
Every human eye (retina) has been equipped by nature with the designed to sense electromagnetic waves within one narrow portion of the electromagnetic spectrum. Light is electromagnetic radiation with a wavelength of 400 nm to 750 nm that belongs to this part of the spectrum. We know and interpret the world around us primarily via light and our sense of vision. From personal experience, there are two things we can instinctively say about light. First, it moves at a tremendous rate, and second, it moves in a straight path. It took a long time for humans to realise that light had a fixed and measured speed. In vacuum, its current recognised value is c = 2.99792458 108m s–1. For many uses, c = 3 108m s–1 is sufficient. The maximum speed achievable in nature is the speed of light in vacuum. This intuitive perception that light travels in a single direction appears to counter what we learned in Chapter 8, namely that light is an electromagnetic wave with a wavelength in the visible range. How can the two facts be reconciled? The explanation would be that the wavelength of light is extremely tiny when compared to the size of everyday items.
As you’ll see in Chapter 10, a light wave may be thought of as travelling in one point to the next along the straight line connecting them. A ray of light seems to be the route, and a beam of light is a collection of similar rays. By using ray picture of light, we examine the processes of light reflection, refraction, as well as dispersion in this chapter. Newton’s basic contributions to mathematics, physics, as well as gravity are often overlooked in favour of his extensive practical and theoretical research on light. In the realm of optics, he made ground-breaking advances. Descartes’ corpuscular model of light was further improved by him. Light energy is thought to be concentrated in small particles known as corpuscles. He also considered that light corpuscles were massless, elastic particles. He could create a rudimentary model of reflection and refraction using his mechanical knowledge. A ball bouncing off a flat plane surface is commonly observed to obey the rules of reflection. The magnitude of the velocity remains constant in an elastic collision. Because there is no force operating parallel to the surface because the surface is smooth, the portion of velocity in this direction stays consistent.
Learn how to solve the below Question:
Reason: No reflection or refraction of light is involved in the formation of rainbow.
- If both assertion and reason are true and reason is the correct explanation of assertion.
- If both assertion and reason are true and reason is not the correct explanation of assertion.
- If assertion is true but reason is false.
- If both assertion and reason are false.
Inspect a compact disc beneath white light & make a note of the colours you see and where they are. Analyse if the spectra are created by diffraction along circular lines centred in the disc’s middle as well as, if that’s so, how far apart they are. If not, figure out what kind of space you’ll need. Examine the spectra of several light sources, including a candle flame, an incandescent bulb, halogen illumination, as well as fluorescent lights, using the CD. Determine the maximum width that would enable the given number of gigabytes of material to be stored using the width of the rows of pits just on compact disc.
If you’ve ever noticed the reds, blues, & greens in a sunny soap bubble as well as puzzled how straw-coloured soapy water could generate them, you’ve encountered one of the numerous phenomena which can only be described by light’s wave nature. The colours visible in an oily substance or in the reflected light from a compact disc are the same. Geometric optics cannot fully explain these and other fascinating phenomena, such as the dispersion of white light into a rainbow of hues when passing through a small slit. Light interacts with tiny things in these situations and reveals its wave qualities. Wave optics is the discipline of optics that studies how light behaves when it has wave properties (especially when it interacts with tiny objects) (sometimes called physical optics). This chapter is all about it.