# In soil, the value of which of the following can be more than 100%? (i) Air Content (ii) Water Content (iii) Void Ratio (iv) Porosity

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In soil, the value of which of the following can be more than 100%?

(i) Air Content

(ii) Water Content

(iii) Void Ratio

(iv) Porosity

1. Only (i)
2. (i) and (ii)
3. (ii) and (iii)
4.  (ii), (iii) and (iv)

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Correct Answer - Option 3 : (ii) and (iii)

Explanation

a) Porosity (n):

The porosity (n) of soil is defined as the ratio of the volume of voids to the total volume of soil.

$η = \frac {V_v}V \times 100\%$

Vv = Volume of voids

V = Total volume of soil

Range of porosity 0 < n < 100%

b) Air content (ac):

The air content of soil (ac) is defined as the ratio of the volume of air voids to the total volume of voids.

$a_c = \frac {V_a}{V_v} \times 100\%$

Va = volume of air voids

Vv = volume of voids

c) Water content (w):

It is also called moisture content. It is the ratio of the weight of water (Ww) to the weight of soil solids (Ws)

$w = \frac {W_w}{W_s};\;w ≥ 0$

Range of water content (w)

w ≥ 0

There is no upper Limit to water content

d) Void Ratio (e)

The ratio of the total volume of voids to the volume of solids is called the void ratio

e = Vv/Vs

e > 0

In general e > 0, i.e. There is no upper limit for the void ratio

Note:

Porosity is always less than 100% but the void ratio may be less than 1 or greater than or equal to 1.

The relation between void ratio and porosity of soil sample is given as:

$n\; = \frac{e}{{1 + e}}$

Where

n is porosity and e is a void ratio.