Question #6734d

1 Answer

#4.56 xx 10^8 "Hz"#

Explanation:

We know,

#c = nulambda# [For an electromagnetic wave]

Where,

#c# = velocity of the wave = #2.998 xx 10^8 "m.s"^"-1"#
#nu# = frequency of the wave and
#lambda# = wavelength of the wave.

According to the question,

#2.998 xx 10^8 color(red)(cancel(color(black)("m")))."s"^"-1" = 657 xx 10^"-3" color(red)(cancel(color(black)("m"))) xx nu#

#nu = 4.56 xx 10^8 "Hz"#