Question

Which of the following statement/s is/are correct with regards to the tangential force which is needed to keep the speeds of different layers of liquid constant? 

(A) It is directly proportional to the velocity difference between the two adjacent layers. 
(B) It is inversely proportional to the area of contact between the two adjacent layers. 
(C) It is inversely proportional to the distance between the two adjacent layers. 
(D) None of the above. 
 

• A. (A), (B) and (C) only
• B. (B) and (C) only
• C. (A) and (C) only
• D. (A) only

Hint:

Tangential force in fluids is influenced by the velocity difference, the area of contact, and the distance between layers of liquid.

Answer 1

The Correct Option is A

Step 1: Statement (A).
Tangential force is directly proportional to the velocity difference between two adjacent layers. This is true because the force needed to maintain different speeds in adjacent liquid layers depends on the difference in velocity. The greater the velocity difference, the higher the tangential force required. Hence, statement (A) is correct.

Step 2: Statement (B).
Tangential force is inversely proportional to the area of contact between the two adjacent layers. When the area of contact between the layers is smaller, the force required to maintain the velocity difference is greater. Thus, statement (B) is correct.

Step 3: Statement (C).
Tangential force is inversely proportional to the distance between the two adjacent layers. As the layers move closer together, the force required to maintain the velocity difference decreases. Therefore, statement (C) is also correct.

Step 4: Conclusion.
All three statements are correct, so the correct answer is (1).

Final Answer: \[ \boxed{\text{(1) (A), (B) and (C) only}} \]