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Define a wavefront. Use Huygen's principle to show diagrammatically the propagation of a wave-front from the instant t_(1)=0 to a later time t_(2)=t. |
Answer» Solution : A wavefront is defined as a surface of CONSTANT phase. Thus, a wavefront is a locus of all those points in space which are vibrating in EXACTLY same phase at any one particular instant of time. Let AB be the position of wavefront at time `t_(1)=0`. Points `A_(1),B_(1),C_(1)`, . . on the wavefront act as SOURCE of light and emit wavelets which travel with speed of light v and will COVER a distance s=vt in time t. draw spheres with points `A_(1),B_(1),C_(1),` . . . as centre and s=vt as the RADIUS. then, common envelope A.B. in the forward direction gives the new wavefront at time `t_(2)=t` as shown in figure. |
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