A beam of light is converging towards a point I on a screen. A plane glass plate whose thickness in the direction of the beam = t, refractive index = $\mathrm{\mu }$, is introduced in the path of the beam. The convergence point is shifted by

• A

  $\mathrm{t}\left(1-\frac{1}{\mathrm{\mu }}\right)\text{ away }$

• B

  $\mathrm{t}\left(1+\frac{1}{\mathrm{u}}\right)\text{ away }$

• C

  $\mathrm{t}\left(1-\frac{1}{\mathrm{\mu }}\right)\text{ nearer }$

• D

  $\mathrm{t}\left(1+\frac{1}{\mathrm{\mu }}\right)\text{ nearer }$