Question

A water tank standing on the floor has two small holes punched in the vertical wall, one above the other. The holes are $2.4\text{cm}$ and $7.6\text{cm}$ above the floor. If the jets of water from the holes hit the floor at the same point, then the height of water in the tank is

• A. $10\text{cm}$
• B. $5\text{cm}$
• C. $20\text{cm}$
• D. $4.8\text{cm}$

Answer 1

The correct option is A $10\text{cm}$

According to question -


Given, range of efflux from both the holes are same.
$\Rightarrow R_1=R_2$
$\Rightarrow h_1(H-h_1)=h_2(H-h_2)$ $[\text{since}R=2\sqrt{h(H-h}]$
$\Rightarrow h_{1}H-h_1^2=h_{2}H-h_2^2$
$\Rightarrow H(h_1-h_2)=h_1^2-h_2^2$
$\Rightarrow H=h_1+h_2$
$\Rightarrow H=2.4+7.6=10\text{cm}$