When two progressive waves of nearly equal frequencies n1 and n2 superimpose then
 

	List – I		List – II
a	Resultant amplitude varies with a frequency	e	$\frac{1}{n_1-n_2}$
b	Resultant wave frequency	f	$\left(\frac{n_1-n_2}{2}\right)$
c	Time interval between two successive maxima of resultant wave	g	$\frac{1}{2\left(n_1-n_2\right)}$
d	Time interval between maxima and minima of the and minima of the	h	$\left(\frac{n_1+n_2}{2}\right)$
		i	$\frac{2}{n_1-n_2}$