Questions

In ionic bonding, the atoms are bound by attraction of oppositely charged ions, whereas, in covalent bonding, atoms are bound by sharing electrons to attain stable electron configurations.

Let the heights of Cat, Table and Turtle be C, T & R respectively.

From the above given figure,

C + T - R = 170 ......(a)

R + T - C = 130 ......(b)

Adding above eqns (a) & (b), we get

2T = 300

T = 150 cm

Hence, the height of the table is 150 cm.

To get a pair of black rings 100 percent certain

27 blue + 17 red + 2 black = 40 rings should be taken out

Then only we can get 100 % a pair of black rings. 

Hygrometer is used for measuring humidity of air.