Question

Why do we periodise date?

Answer 1

Explanation:

15. Which of the following salts can produce only two types of radicals?

Options:

(a)

NaKCO3

(b)

CaOCl2

(c)

NH HSO 4 4

(d)

Na NH HPO  4 4 

16. The weight of an empty China dish is 39 g and when a saturated solution of potassium

nitrate is poured into it, its weight is 108 g at

50C

. After evaporating the solution to

dryness, if the weight of the dish along with the crystals is 72 g then the solubility of

potassium nitrate at

50C

is _____.

Options:

(a) 83.9

(b) 95.6

(c) 91.6

(d) 87.4

17. If the roots of the quadratic equation

2

ax bx c    0

are



and



, then the equation

whose roots are

2 

and

2



is

Options:

(a)

 

2 2 2 2 a x b ac x c     2 0

(b)

2 2 2 2 a x b x c    0

(c)

 

2 2 2 2 a x b ac x c     2 0

(d)

 

2 2 2 2 a x b ac x c     2 0

18. If

2 2

Answer 2

James Mill divided the Indian history into three periods: Hindu, Muslim and British.

According to  Mill, Only British rules, culture and laws could make indians civilised.

There are significant sources to study the periods of events and by studing different historical evidences a string of time periods can be formed.