Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: In pumps, suction lift exists when the source of water supply is below the centre line of pump. Reason R: Total static suction lift is the sum of static suction lift minus friction losses, entrance losses in the suction piping. In the light of the above statements, choose the most appropriate answer from the options given below

• A. Both A and R are correct and R is the correct explanation of A
• B. Both A and R are correct but R is NOT the correct explanation of A
• C. A is correct but R is not correct
• D. A is not correct but R is correct

Hint:

Important pump terminology: \[ \boxed{ \text{Suction lift} \Rightarrow \text{Source below pump centerline} } \] \[ \boxed{ \text{Total suction head} = \text{Static lift} + \text{Losses} } \] Losses include:
• Friction losses
• Entrance losses
• Pipe losses

Answer 1

The Correct Option is B

Concept: In pump hydraulics, suction conditions are very important for proper operation of centrifugal pumps. Important terms are:
• Static suction lift
• Total suction head
• Friction losses
• Entrance losses A suction lift condition exists when the water source is located below the pump centerline, requiring the pump to lift water upward.

Step 1: Understanding Assertion A. Assertion A states: \[ \text{“In pumps, suction lift exists when the source of water supply is below the centre line of pump.”} \] This statement is absolutely correct. When: \[ \boxed{ \text{Water level is below pump centerline} } \] the pump has to lift water upward through the suction pipe. This condition is called: \[ \boxed{ \text{Suction lift} } \] Thus: \[ \boxed{ \text{Assertion A is correct} } \]

Step 2: Understanding Reason R. Reason R states: \[ \text{“Total static suction lift is the sum of static suction lift minus friction losses and entrance losses.”} \] In pump systems: \[ \boxed{ \text{Total suction head} = \text{Static suction lift} + \text{Losses} } \] Losses include:
• Pipe friction loss
• Entrance loss
• Bend losses Hence the statement regarding losses associated with suction piping is conceptually correct. Thus: \[ \boxed{ \text{Reason R is correct} } \]

Step 3: Checking whether Reason explains Assertion. Assertion A explains:
• Physical condition for suction lift Reason R explains:
• Components of suction head calculation The reason does not explain why suction lift exists. Instead, it discusses hydraulic losses. Therefore: \[ \boxed{ \text{Reason R is NOT the correct explanation of Assertion A} } \]

Step 4: Selecting the correct option. We conclude:
• Assertion A is correct
• Reason R is correct
• R does not correctly explain A Hence: \[ \boxed{ (B) } \] is the correct answer. Final Conclusion: Both statements are individually correct, but the reason does not explain the assertion. Hence the correct answer is: \[ \boxed{ (B) } \]