Question

Statement (I): In the operation of reciprocating pumps, slip can sometimes be negative.

Statement (II): Under conditions of high speed, long suction pipes (without capitation) and short delivery pipes, inertia pressure can be relatively rather high, causing the delivery valve to open before the discharge stroke begins. 

1. Both Statement (I) an Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
2. Both Statement (I) and Statement (II) are individually true but Statement (II) is not the correct explanation of Statement (I) 
3. Statement (I) is true but Statement (II) is false 
4. Statement (I) is false but Statement (II) is true 

Answer 1

Correct Answer - Option 1 : Both Statement (I) an Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)

Concept:

In a reciprocating pump energy conversion takes place due to reciprocating action of the piston.

Slip occurs due to leakage in pump, incomplete filling of cylinder & imperfection in valve operation due to inertia.

Slip is definded as, Slip = Q_theo - Q_act

% slip = ((Q_theo- Q_act)/Q_theo) × 100 = (1 - C_d) × 100

Where C_d = Coefficient of discharge

When Q_theo > Q_{act ,}Slip will be positive.

When Q_theo < Q_act, Slip will be negative.

Negative slip happens when

Delivery pipe is short.

Suction pipe is long.

Pump is running at high speed.

So in the operation of reciprocating pumps, slip can sometimes be negative.

So here both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I).