NEET Practice Questions (MCQs) with Answers & Solutions

  $1.3\times {10}^{-20} \mathrm{g}$

  $5.01\times {10}^{-21} \mathrm{g}$

  $3.72\times {10}^{-23} \mathrm{g}$

  $1.4\times {10}^{-21} \mathrm{g}$

,

,

and

:

S : Avogadro's number was proposed $6.019\times {10}^{23}$ on O-16 scale and $6.02\times {10}^{23}$ on C-12 scale.

E : The numerical value of Avogadro's number depends upon the atomic mass scale.

1.  S is correct but E is wrong
2.  S is wrong but E is correct
3.  Both S and E are correct and E is correct explanation of S
4.  Both S and E are correct but E is not correct explanation of S

,

,

and

:

S : An element may have variable equivalent mass.

E : Such elements should possess variable valency. 

1.  S is correct but E is wrong
2.  S is wrong but E is correct
3.  Both S and E are correct and E is correct explanation of S
4.  Both S and E are correct but E is not correct explanation of S

  3   2   -2   (+)1/2

  4   0   0    (-)1/2

  3   2   -3   (+)1/2

  5   3   0   (-)1/2

0

2

4

6

2

0

3

1

Electron 1             3            0             0           -1/2

Electron 2             4            0             1           1/2

Electron 3            3             2             0           1/2

Electron 4            3             1             0           -1/2

The correct order of decreasing energy of these electrons is - 

(A) Electron 3 > Electron 1 > Electron 4> Electron 2

(B) Electron 4> Electron 2 > Electron 3 > Electron 1

(C) Electron 3 > Electron 2 > Electron 4 > Electron 1

(D) Electron 2 > Electron 4 > Electron 3 > Electron 1

Ultraviolet light

X-rays

Visible light

y-rays

3 x 10^-14m

1.3 x 10^-14m

2.1 x 10^-14m

4.3 x 10^-14m

510nm

420nm

589nm

622nm