Mala has a collection of bangles. She has 20 gold bangles and 10 silver bangles. What is the percentage of bangles of each type? Can you put it in the tabular form as done in the above example?

A current balance is a device to measure magnetic forces. It is constructed from two parallel coils, each with an average radius of 12.5 cm. The lower coil rests on a balance, it has 20 turns and carries a constant current of 4.0 A. The upper coil, suspended 0.314 cm above the lower coil, has 50 turns and a current that can be varied. The reading of the balance changes as the. magnetic force on the lower coil changes. What current is needed in the upper coil to exert a force of 1.0 N on the bottom coil?

A man went door to door posing as a goldmith he promised to bring back the glitter of old and dull gold oranments an unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution the bangles sparkled like new but their weight was reduced drastically the lady was upset but after a futile argument the man beat a hasty retreat can you play the detective to find out the nature of the solution he had used?

A farmer has a supply of chemical fertilizer of type A which contains 10 % nitrogen and 6% phosphoric acis and type B fertilizer which contains 5% nitrogen and 10% phosphoric acid. After testing the soil condition of a field, it is found that at least 14 kg of nitrogen and 14 kg of phosphoric acid are required for a good crop. The fertilizer type A costs Rs 5 per kg and type B Rs 3 per kg. How many kilograms of each fertilizer should be used to meet the requirements and the cost be minimum? Using LPP, solve the above problem graphically.

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.

Statement-1(Assertion and Statement -2 (reason) Each of these examples also has four alternative choices, only one of which is the correct answer. You have select the correct choice as given below. Statement -1 If N=(1/0.4)^20 , then N contains 7 digit before decimal. Statement -2 Characteristic of the logarithm of N to the base 10 is 7.

A company sells biscuits. For packing purpose they are using cuboidal boxes : box A to 3cm xx 8cm xx 20cm , box B to 4cm xx 12cm xx 10 cm . What size of the box will be economical for the company? Why? Can you suggest any other size dimensions which has the same volume but is more economical than these?