Questions

An amorphous or non-crystalline solid is a solid that lacks the long-range order that is characteristic of a crystal. In Brief, An amorphous solid is any noncrystalline solid in which the atoms and molecules are not organized in a definite lattice pattern. Such solids include glass, plastic, and gel.

Quartz glass (SiO2) is an amorphous solid due to its short range order of constituent particles. Note Quartz is a crystalline solid while quartz glass is an amorphous solid.

Annie Besant (1847-1933) – political reformer, women's rights activist, theosophist and Indian nationalist is known as the grand old lady of Indian nationalism.

Page swapping or page replacements are called page cannibalizing.

Quantity 1:
Let the first pipe alone takes x hours to fill the
tank.
⇒The second and third pipes will take (x-5) and
(x-9) hours respectively.
According to the given information:
∴ 1x-9

⇒ (x-9)(2x-5) = x2 – 5x
⇒ 2x2 – 5x – 18x + 45 = x2 – 5x
⇒ x
2 -18x + 45 = 0
⇒ (x-15) (x-3) = 0
⇒ x = 15, 3

The first pipe can take 15 hours to fill the kund.
∵ 3 hours doesn’t satisfy the statement.
Quantity 2:
∴ Time taken by second pipe = x-5
⇒ Time taken by second pipe = 15-5 = 10hours
∴ Time taken by third pipe = x -9
⇒ Time taken by third pipe = 15- 9 = 6 hours
Now,

Net part filled in 1 hour = 115+110+16
⇒ Net part filled in 1 hour = 4+6+1060
⇒Net part filled in 1 hour = 2060=13
∴The Kund will be full in 3/1 hours if all the pipes are opened simultaneously
Now, comparing
15 > 3
Thus, Quantity 1 > quantity 2

Hardness can be removed by adding sodium carbonate (washing soda) or by passing the water through an ion-exchange column.

Hardness in water is caused by dissolved magnesium ions and calcium ions. These can get into the water when it comes into contact with limestone and other rocks that contain calcium compounds. This can happen, for example, when rainwater flows over these rocks on its way to a reservoir.

Hardness in water is of two types. They are :

1. Temporary hardness

2. Permanent hardness

1. Temporary hardness:: Temporary hardness is caused by dissolved calcium hydrogen carbonate.

2. Permanent hardness:: Permanent hardness is caused by dissolved calcium sulfate. Unlike temporary hardness, it is not removed by boiling the water.