SOME GUESS QUESTIONS FOR BOARD EXAM 2017

 ➤ What do you mean by Diffraction of light? Explain formation of a
pattern of fringes obtained on the screen and plot variation of Intensity
with angle in single slit diffraction experiment.
2+2+1

➤ What is interference of light? Write two essential conditions for
sustained interference pattern. How the fringe pattern is affected by (i)
moving screen closer to the planes of slits and (ii) increasing the
reparation between two slits.
1+2+2


➤ What are Coherent Sources? Derive mathematical expression for width
of interference fringes obtained in Young’s double slit Experiment.
With the help of graph, show the variation of intensity pattern in YDSE.
1+3+1


➤ How is wave front and secondary wavelets defined? Verify laws of
reflection or laws of refraction on the basis of Huygens’s wave theory.



 ➤What is meant by ‘normal adjustment’ in case of an astronomical
telescope? What are two main Considerations of designing the
“objective” of an astronomical telescope? Obtain an expression for the
angular magnifying power and the length of the tube of an astronomical
telescope in its ‘normal adjustment’ position.
1+1+3



➤ Draw a labelled ray diagram for the formation of image by a Compound
microscope. Derive expression for its total magnification, when final
image is formed at the near point. Why both objective and eyepiece of a
compound microscope must have their short focal lengths?

2+2+1