Minor Energy Losses

Q. The head loss due to sudden expansion is expressed by

1. $\frac{V_1^2-V_2^2}{2g}$
2. ${\left(\frac{V_1-V_2}{2g}\right)}^2$
3. ${\left(\frac{V_1-V_2}{g}\right)}^2$
4. $\frac{(V_1-V_2{)}^2}{2g}$

Q. The loss of head at various pipe fittings is given by the expression $K\frac{V^2}{2g}$. If values of K were 0.40, 0.90, 1.5 and 2.2, then these would correspond respectively to

1. $\text{Foot valve of pump,}{45}^{\circ }elbow,{90}^{\circ }\text{elbow and close return bend}$
2. ${45}^{\circ }\text{elbow,}{90}^{\circ }\text{elbow, foot valve of pump and close return bend}$
3. ${90}^{\circ }\text{elbow, foot valve of pump, close return bend and}{45}^{\circ }\text{elbow}$
4. $\text{Foot valve of pump, close return bend,}{45}^{\circ }\text{elbow and}{90}^{\circ }\text{elbow}$

Q. A pipeline of 5 cm diameter is reduced abruptly to 2.5 cm diameter at a section to enable measurement of the water flowing through it. The loss of head at the contraction is 0.5 m. Given that, in metric units,
$\sqrt{2g}=4.43\text{and}\sqrt{g}=3.132,$
the mean velocity in the reduced section will be

1. 0.5 m/sec
2. 1.1075 m/sec
3. 1.566 m/sec
4. 4.43 m/sec

Q. The cavitation and pitting can be prevented by creating which one of the following conditions?

1. Reducing the pressure head
2. Reducing the velocity head
3. Increasing the elevation head
4. Reducing the piezometric head

Q. A and B are at the same elevation of 2.5 m above datum in the valve and pipe line shown in the given figure. Velocity head of 0.5 m, head loss in valve of 0.2 m and pressure head of 2.5 m are the parameters at A. Piezometric head at B is equal to

1. 5.5 m
2. 5.3 m
3. 5.0 m
4. 4.8 m