SHOW REFRACTION THROUGH A GLASS SLATE WITH NEAT DIAGRAM

Refer to the attachment

When the light ray travels from rarer to denser medium it bends towards the normal while that of rarer to denser goes away from normal.

Explanation:

A ray of light EF in air is incident on the glass surface PQ at point O. As the ray EO enters from air (rarer medium) to glass (denser medium), the ray bends towards normal and follows the path OO' inside the glass slab. At point O', refraction enters from glass (denser medium) to air (rarer medium) the ray bends away from normal and follows the path O'H outside the glass slab. Here the ray EF is called incident ray, OO' called refracted ray and O'H called emergent ray.

As per the laws of refraction, the emergent ray OlH will be parallel to the incident ray EF. The perpendicular distance O'I=x between the original path of incident ray and the emergent ray is called the lateral displacement.

Note: When the light ray has incidental in a medium and after this the light ray reflected in different media and then comes out in the same medium as it was incidence then the incident ray and emergent ray are parallel to each other.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.