$A$ parallel plate air capacitor is charged to a potential difference of $V$. After disconnecting the battery,the distance between the plates of the capacitor is increased using an insulating handle. As a result,the potential difference between the plates:

$A$ source of sound of frequency $640 ~Hz$ is moving at a velocity of $\frac{100}{3} ~m/s$ along a road,and is at an instant $30 ~m$ away from a point $A$ on the road (as shown in figure). $A$ person standing at $O$,$40 ~m$ away from the road,hears sound of apparent frequency $v^{\prime}$. The value of $v^{\prime}$ is (velocity of sound $= 340 ~m/s$). (in $~Hz$)

Enzymes are sensitive to

Which of the following products is formed when $SiF_4$ reacts with water?

If the area of an equilateral triangle inscribed in the circle $x^2 + y^2 + 10x + 12y + c = 0$ is $27\sqrt{3}$ sq. units,then $c$ is equal to:

Which of the following is absent in polluted water?