Nodes in the resulting standing wave

[kingyof2thejring]

Homework Statement

Microwaves of frequency 10^10 Hz are beamed directly at a metal
reflector. Neglecting the refractive index of air, determine the spacing
between successive nodes in the resulting standing wave.

Homework Equations

The Attempt at a Solution

dont know what to do here

 

[kingyof2thejring]

disturbance is zero at nodes for x=0, lambda/2, 3/2*lambda...
so lambda=c/f
and the the spacing is lambda/2 at the nodes