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प्रश्न
A change in the physical state can be brought about
विकल्प
only when energy is given to the system
only when energy is taken out from the system
when energy is either given to or taken out from the system
without any energy change
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उत्तर
when energy is either given to or taken out from the system
When energy is given to the system the solid state changes to liquid. When energy is taken out from a liquid it changes to solid e.g., ice changes to water and water to water vapours when heat energy is given. Water vapours or steam condense to water and water freezes to ice when energy is decreased.
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संबंधित प्रश्न
TRUE \ FALSE
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Fill in the blank:
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1. first shell
2. second shell
3. third shell and
4. fourth shell
Who originated the word ‘atom’ ?
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Fill in the blank
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State two observations which show that atom is not indivisible.
An atom of element E contains 3 protons, 3 electrons and 4 neutrons :
(a) What is its atomic number?
(b) What is its mass number?
(c) Write the electronic configuration of the element E.
(d) State whether element E is a metal or non-metal. Why?
(e) What type of ion, cation or anion, will be formed by an atom of element E? Why
(f) Write the symbol of the ion formed by an atom of element E.
(g) What could element X be?
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Draw the electron dot structure of this compound.
Elements X and Y have 1 and 7 electrons in their outermost shell respectively.
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K: Potassium:: C: ______.
The volume occupied by 1 mole of a diatomic gas at S.T.P is ______
The graphite refill used is pencil is made of element called ______.
The most abundant type of atom is the universe is ______.
A small block slides down on a smooth inclined plane, starting from rest at time t = 0. Let Sn be the distance travelled by the block in the interval t = n – 1 to t = n. Then, the ratio `S_n/(S_(n + 1))` is ______.
