JEE Main & Advanced
Sample Paper
JEE Main - Mock Test - 18
question_answer
A stone is dropped into a quiet lake and waves move in a circle at a speed of \[3.5\text{ }cm/sec.\]At the instant when the radius of the circular wave is\[7.5\text{ }cm\]. Then, the rate of increasing in the enclosed area is \[k\,\pi ,\] then k is