The atomic number of an element is 16.Predict
i) the number of valence electrons in its atom
ii)its valency
iii) its group number
iv) whether it is a metal or a non-metal
v) the nature of oxide formed by it
vi)the formula of its chloride
Draw a ray diagram to show the refraction of light through a glass prism. Mark on it
a) the incident ray, b) the emergent ray and c) the angle of deviation.
Explain with the help of a diagram, how we are able to observe the sunrise about two minutes before the sun gets above the horizon?
An object is placed between infinity and the pole of a convex mirror. Draw a ray diagram and also state the position, the relative size and the nature of the image formed.
What is the principle of reversibility of light? Show that the incident ray of light is parallel to the emergent ray of light when light falls obliquely on a side of a rectangular glass slab.
What eye-defect is myopia? Describe with a neat diagram how this defect of vision can be corrected by using a suitable lens?
Myopia is a defect in which, an eye can see nearby objects clearly but cannot see distant objects distinctly. Myopia is also known as short-sightedness or near sightedness.
Myopia is caused by the elongation of the eyeball or excessive curvature of the converging system of eye.
The image is formed in front of retina.
Myopia can be corrected using concave lens.
Give an example to illustrate that indiscriminate use of pesticides may result in the degradation of the environment.
List any, four reasons for vegetative propagation being practised in the growth of some type of plants.