Statement I A bubble comes from the bottom of a lake to the top. Statement II Its radius increases.

Question

Each of these questions contains two statement: Statement I (Assertion) and Statement II (Reason). Each of these questions also has four alternative choices, only one of which is correct answer. You have to select the correct choice in the codes (a), (b), (c) and (d) in the given below 

(a) Statement I is true, Statement II is true; Statement II is not a correct explanation of Statement I 

(b) Statement I is true; Statement II is false 

(c) statement I is false, Statement II is true

(d) Statement I is true, statement II is true: Statement II is a correct explanation of Statement I

Statement I A bubble comes from the bottom of a lake to the top. 

Statement II Its radius increases.

Answer 1

The correct option is (a) Statement I is true, Statement II is true; Statement II is not a correct explanation of Statement I.

Explanation:

Since, the fluid moves from higher pressure to lower pressure and in a fluid, the pressure increase with increase of depth. Hence, the pressure p_o will be lesser at the top than that at the bottom (p_o + hpg). So, the air bubble moves from the bottom to the top and does not move sideways, since the pressure is same at the same level. Further, in coming from bottom to top the pressure decreases. According to Boyle's law pV = constant. 

Therefore, if pressure decreases, the volume increases, it means radius increases.