Question 1 :
The glancing angle of incidence is $$10^{\circ}$$. What will be the glancing angle of reflection?

Question 2 :
When a light of wavelength $$4000$$ $$\displaystyle \overset { \circ  }{ A } $$ in vacuum travels through the same thickness in diamond and water separately, the difference in the number of waves is $$200$$. Find the thickness, if refractive indices of diamond and water are $$\displaystyle \frac { 5 }{ 2 } $$ and $$\displaystyle \frac { 4 }{ 3 } $$ respectively.

Question 3 :
The final image in an astronomical telescope is _______ the original object&#160;. Fill in the gap.<br/>