Does the transfer of energy takes place when you push a huge rock with all your might and fail to move it ? Where is the energy you spent going ?

If you are 100 cm in front of a mirror , where does your image appear to be ? If you move towards the mirror ,how does your image move ?

When light travels from a rarer to denser medium,the speed decreases.Does the decrease in speed imply a decrease in the energy carried by the light wave?Justify you answer.

One of the two set squares in your instrument box has angles of measure 30^(@) - 60^(@) - 90^(@) Take two such identical set - squares .Place them side by side to form a kite like the one shown here . How many lines of symmetry does the shape have ? Do you think that some shapes may have more than one line of symmetry ?

Direction. In the follwing questions, a statement of assertion is followed by a statement of reason. While answering a question, you are required to choose the correct are out of the given four responses and mark it as (A). If both assertion and reason are true and reason is the correct explanation of the assertion, (B) if both assertion and reason are true but reason is not correct explanation of the assertion. (C) if asssertion is true, but reason if false, (D) if both assertion and reason are false Assertion : The energy of a charged particle does not change, when it moves inside the magnetic field. Reason: It is because, force on the charged particle due to the magnetic field acts perpendicular to its path.

classically an electron can be in any orbit around nucleus of an atom. Then what determines the typical atomic size? Why is an atom not, say, thousand times bigger than its typical size? Thequestion had greatly puzzled Bohr before he arrived at his famous model of the atom that you have learnt in the text. To simulate what he might well have done before his discovery, let us play as followswith the basic constants of nature e, me, c and see if we can get a quantity with the dimensions of length that is roughly equal to the known size of an atom (~ 10 m).- You will find that the length obtained above is many orders of magnitude smaller than the atomic dimensions. Further, it involves c. But energies of atoms are mostly in non-relativistic domain where c is not expected to play any role. This is what may have suggested Bohr to discard c and look for else h had already made its appearance elsewhere. Bohr lay in recognising that h, m_e , and e will yield the right atomic size. Construct a quantity with the dimension of length from h, me, and e and confirm that its numerical value has indeed the correct order of magnitude.