question_answer

If prism angle \[\alpha =1{}^\circ ,\] \[\mu =1.54,\] distance between screen and prism  = 0.7 m, distance between prism and source \[a=0.3\,m,\] \[\lambda =180\pi \,nm,\] then in Fresnal biprism find the value of\[\beta \](fringe width).

A)  \[{{10}^{-4}}m\]                             

B)  \[{{10}^{-3}}mm\]

C)  \[{{10}^{-4}}\times \pi m\]        

D)         \[\pi \times {{10}^{-3}}m\]