Bank Exams Questions

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Graphite is a covalent-network type of crystalline solid.

There are two main categories of solids.

1. Crystalline solids and

2. Amorphous solids.

Crystalline solids are those in which the atoms, ions, or molecules that make up the solid exist in a regular, well-defined arrangement.

There are four types of crystalline solids :

Ionic solids :— Made up of positive and negative ions and held together by electrostatic attractions. They’re characterized by very high melting points and brittleness and are poor conductors in the solid state. An example of an ionic solid is table salt, NaCl.

Molecular solids :— Made up of atoms or molecules held together by London dispersion forces, dipole-dipole forces, or hydrogen bonds. Characterized by low melting points and flexibility and are poor conductors. An example of a molecular solid is sucrose.

Covalent-network (also called atomic) solids :— Made up of atoms connected by covalent bonds; the intermolecular forces are covalent bonds as well. Characterized as being very hard with very high melting points and being poor conductors. Examples of this type of solid are diamond and graphite, and the fullerenes. As you can see below, graphite has only 2-D hexagonal structure and therefore is not hard like diamond. The sheets of graphite are held together by only weak London forces!

Metallic solids :— Made up of metal atoms that are held together by metallic bonds. Characterized by high melting points, can range from soft and malleable to very hard, and are good conductors of electricity.

Given, y/(x - z) = (y + x)/z = x/y
yz = xy + x2 - yz - xz ....(1)
Also xy = yx-z ⇒x2 -xz = y2 ....(2)
Using (1) and (2), we get yz = xy - yz + y2
2yz = xy + y2
2z = x + y
Only option (B) satisfies the equation.

First is used to prepare the second.

Hence, Wax : Grease :: Milk : Curd.

Given number of girls are twice that of boys.

--> G=2B and G+B = 60 

Therefore,  G=40 and B= 20

Given Laxmi ranked 27th from the top and 9 boys are ahead of Laxmi.

Therefore, There are 17 girls ahead of Laxmi. 

Therefore, Number of girls who ranked after Laxmi = 40 - (17+1) = 22.

Garbage truck.

It’s true, a garbage truck has 4 wheels and lots of flies because flies like garbage. Here flies means insects like houseflies, mosquitoes, ... It doesn't mean that it flies in the air.

FRIEND : FPIBNZ

Follows a pattern that,

F - F

R- second letter to left of R i.e, P

I - I

E - Third letter to left of E i.e, B

N - N

D - Fourth letter to left of D i.e, Z

Similarly, for PATRON 

P - P

A -  second letter to left of A i.e, Y

T - T

R - Third letter to left of R i.e, O

O - O

N - Fourth letter to left of N i.e, J

PATRON : PYTOOJ

Therefore, FRIEND : FPIBNZ :: PATRON : PYTOOJ