The atomic number of an element is 16.Predicti) the number of va

Subject

Science

Class

CBSE Class 10

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 Multiple Choice QuestionsShort Answer Type

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21.

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


The electronic configuration of element 16: 2,8,6

i) The number of valence electrons 6.

ii)Its valency is 8-6 =2.

iii) Its group number is 16.

iv)It is a non-metal.

v) the nature of oxide is acidic.

vi) The valency of chloride is 1 and valency of X (=16) is 2 thus the formula is XCl2.

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22.

State any four characteristics of the image of an object formed by a plane mirror.

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23.

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.

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24.

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?

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25.

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.

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26.

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.

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27.

What eye-defect is myopia? Describe with a neat diagram how this defect of vision can be corrected by using a suitable lens?

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28.

What is meant by biological magnification?

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29.

Give an example to illustrate that indiscriminate use of pesticides may result in the degradation of the environment.

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30.

List any, four reasons for vegetative propagation being practised in the growth of some type of plants. 

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