In an $FM$ system, a $7\, kHz$ signal modulates a $108\, MHz$ carrier such that the frequency deviation is $50\, kHz$. The carrier swing is: (in $ kHz$)

Which one of the following pairs of compounds illustrates the law of multiple proportions?

The rate of steady volume flow of water through a capillary tube of length $l$ and radius $r$ under a pressure difference of $P$ is $V$. This tube is connected with another tube of the same length but half the radius in series. Then the rate of steady volume flow through them is (The pressure difference across the combination is $P$).

Which of the following statements is not correct?

If the direction cosines of two lines are given by $l+m+n=0$ and $l^2-5m^2+n^2=0$,then the angle between them is

Which of the following statements is not correct?