The distance between the first and the sixth bright fringes formed in Young’s double slit experiment (measured by a spectrometer) is found to be 12.5 mm. The separation between the slits is 0.12 mm and the distance of the screen from the slits is 60 cm. Calculate :
(i) the fringe width
(ii) the wavelength of the light used (in nm).
(i) What is the difference between the electric field vector E at any point in the path of a linearly polarized light and that of an un-polarized light ?
(ii) Briefly describe how a given beam of light can be analysed and determined if it is linearly polarized or un-polarized.
A plano-convex lens made of glass (n = 1 5) has a focal length 10.0 cm.
(i) Calculate the radius of curvature of its curved surface.
(ii) If an identical plano-convex lens is placed in contact with the first (plane surfaces facing each other), what will be the power of the combination (in dioptres) ?
(i)
Given n =1.5
f = 10 cm
Since the line is plano convex :
∴R1 (radius of curvature of plane surface) = ∞
R2 = ?
We know that,
ii) When an identical planoconvexx lens is placed in contact with the first one. Then focal length of combination is given by
(i) State the three conditions for the formation of a pure spectrum.
(ii) Draw the ray diagram illustrating the measurement of the angle of a prism using a spectrometer.
The work function for sodium is 2.28 eV. [3]
(i) What is the minimum energy for a quantum of radiation to cause photoelectric emission from a sodium surface ?
(ii) Calculate the wavelength of this radiation.