1. Verification of OHM’s Law

Ohm's law states that under constant temperature, the current passing through conductor is directly proportional to potential difference applied across it.

i.e., V = IR

Where,

V = potential difference

R = Resistance (constant)

I = Current

Ohm's law can be verified using following circuit diagram, 

2. AC Generator

AC generator is a device which converts mechanical energy into alternating form of electrical energy. It works on the principle of electromagnetic induction. When a closed coil is rotated in a uniform magnetic field with its axis perpendicular to the magnetic field, the magnetic field lines passing through the coil change and an induced emf is produced causing the flow of current in it. 

3. DC generator

DC generator is a device which converts mechanical energy into the direct form of electrical energy.

DC generator has split ring commutator instead of slip rings in the AC generator. Split ring commutator consists of two semi-cylindrical brass rings S1 and S2 rigidly attached to the two ends of the armature coil. As the armature coil rotates, the two split rings also rotate about the same axis of rotation. 

4. Human eye 

The human eye is an organ that reacts to light in many circumstances. As a conscious sense organ the human eye allows vision; rod and cone cells in the retina allow conscious light perception and vision, including color differentiation and the perception of depth. The human eye can distinguish about 10 million colors. 

5. Defects of vision and their correction

(i) Myopia (near sightedness) and its correction with convex lens:

Myopia is the defect of the eye vision due to which a person can see the nearby objects clearly but cannot see the far objects so distinctly. In this case, the image is formed in front of the retina. Myopia can be corrected by using a concave lens of suitable focal length in the spectacles of such a person.

(ii) Hypermetropia (far sightedness) and correction with concave lens:

Hypermetropia is the defect of the eye vision due to which a person can see distant objects distinctly but cannot see nearby objects so clearly. In this case, the image is formed behind the retina. 

Hypermetropia can be corrected by using convex lens of suitable focal length in spectacles.

6. Refraction of Light through a Glass Prism

Prism is a transparent optical object with flat, polished surfaces that refract light. At least two of the flat surfaces must have an angle between them.

When a ray of light enters the glass prism it gets deviated two times. First when it enters the glass prism and second when it comes out of the prism. The emergent ray is divided by an angle to the incident ray. This angle is called the angle of deviation.

7. Dispersion of White Light by the Glass Prism

When a beam of white light is passed through a glass prism, it is split up into a band of colours called spectrum. This is called dispersion of white light. The spectrum of white light has the colours violet, indigo, blue, green, yellow, orange and red (VIBGYOR).

8. Recombination of the Spectrum of White Light

When a beam of white light is passed through a glass prism, it is split up into its component colours. When these colours are allowed to fall on an inverted glass prism it recombines to produce white light.

9. Rainbow Formation

A rainbow is a natural spectrum appearing in the sky after a rain shower. It is caused by the dispersion of sunlight by water droplets present in the atmosphere. The water droplets act like small prisms. They refract and disperse the sunlight which again reflected internally and finally refracted again when coming out of the rain drops. Due to the dispersion and internal reflection of sunlight by the water droplets, we see the rainbow.

10. Refraction of Light Through Rectangular Glass Slab

Refraction through a rectangular glass slab. ... Emergent ray is parallel to incident ray because the extent of bending of the ray of light at the opposite parallel faces which are PQ (air-glass interface) and SR (glass-air interface) of the rectangular glass slab is equal and opposite.  

Atmospheric Refraction Effects At Sunrise and Sunset 

The layers of air nearer to earth are denser than those above it. At sunrise and sunset when the sun is below the horizon, the light rays starting from sun are incident on these layers. They pass through successively denser layers and thus get bent more and more towards the normal until they fall upon the eye of the observer O. To the observer O these rays appear to come from S’ which is above horizon. It is for this reason that the sun is visible to us a little before it rises above the horizon and so also till a little later it sets below the horizon. The difference of time is about 2 minutes each for early rise and late setting of the Sun 

Reddening Of The Sun At Sunrise And Sunset 

The reddish appearance of the sun at sunrise or sunset is due to scattering of light by the molecules of air and other fine particles in the atmosphere have size smaller than the wavelength of visible light from the sun near the horizon. 

Apparent Star Position Due to Atmospheric Refraction 

 and Colourful World. The twinkling of stars is also due to atmospheric refraction. Because of the increasing refractive index, the starlight bends downwards (ie towards the normal) and thereby the apparent position of the star is slightly higher than its actual position.