In a variable head permeability test, the head was noted to fall from 100 cm to 75 cm in 2.5 minutes. If the time required to drop head further remains same, the final head of water is_____ cm.

56.26

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29.36

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48.39

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76.17

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Solution

The correct option is A 56.26
If the time required to drop head from $(h_{1}) t o (h_{2}) a n d (h_{2}) t o (h_{3})$ is same.

$t_{1} = t_{2}$

$h_{2} = \sqrt{h_{1} h_{3}}$

$\frac{h_{1}}{h_{2}} = \frac{h_{2}}{h_{3}}$

$∴ h_{3} = \frac{h_{2}^{2}}{h_{1}} = \frac{75^{2}}{100} = 56.25 c m$

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In a variable head permeability test, the head was noted to fall from 100 cm to 75 cm in 2.5 minutes. If the time required to drop head further remains same, the final head of water is_____ cm.

The correct option is A 56.26If the time required to drop head from (h1) to (h2) and (h2) to (h3) is same. t1=t2 h2=√h1h3 h1h2=h2h3 ∴h3=h22h1=752100=56.25cm

The correct option is A 56.26
If the time required to drop head from $(h_{1}) t o (h_{2}) a n d (h_{2}) t o (h_{3})$ is same.

$t_{1} = t_{2}$

$h_{2} = \sqrt{h_{1} h_{3}}$

$\frac{h_{1}}{h_{2}} = \frac{h_{2}}{h_{3}}$

$∴ h_{3} = \frac{h_{2}^{2}}{h_{1}} = \frac{75^{2}}{100} = 56.25 c m$