Radius of the well = 2.8/2 = 1.4 m
Depth of the well = 28 m
Hence, the volume of earth dug out
![\[\begin{array}{*{35}{l}} =~\pi {{r}^{2}}h \\ =\text{ }\left( 22/7 \right)\text{ x }1.4\text{ x }1.4\text{ x }28 \\ =\text{ }17248/100\text{ }=\text{ }172.48\text{ }{{m}^{3}} \\ \end{array}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-1f702326a6f737429f9d01642285328c_l3.png "Rendered by QuickLaTeX.com")
Area of curved surface
![\[\begin{array}{*{35}{l}} =\text{ }2\pi rh \\ =\text{ }2\text{ x }22/7\text{ x }1.4\text{ x }28 \\ =\text{ }246.40\text{ }{{m}^{2}} \\ \end{array}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-6770e39829e8860b9b986f43a4ad8a63_l3.png "Rendered by QuickLaTeX.com")
the cost of plastering at the rate of
![\[\begin{array}{*{35}{l}} Rs\text{ }4.50\text{ }per\text{ }sq\text{ }m \\ =\text{ }Rs\text{ }246.40~x~4.50 \\ =\text{ }Rs\text{ }1108.80 \\ \end{array}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-684e2c11f13289812b007e49680dcecd_l3.png "Rendered by QuickLaTeX.com")
How many cubic meters of earth must be dug out to make a well 28 m deep and 2.8 m in diameter? Also, find the cost of plastering its inner surface at Rs 4.50 per sq meter.
How many cubic meters of earth must be dug out to make a well 28 m deep and 2.8 m in diameter? Also, find the cost of plastering its inner surface at Rs 4.50 per sq meter.
and 
, internal resistance 
and 
, connected in parallel. The equivalent emf of the combination is- (A) 
(B) 
(C) 
(D) 
and 
are collinear, prove that 
and 
be three points such that area of a 
is 4 sq units, find the value of 
.
and 
is 35 sq units.
and 
are collinear.
and 
are collinear.
and 
are collinear.
and 