# SPH102 CAT2 March 2023 SOLVED

(1) An object is placed at a distance of 0.2 m from a lens of focal length 0.4m. Use ray diagrams to locate the image formed if the lens is

(i) concave

(ii) Convex

(2) An object placed in front of a concave lens of focal length 0.4 m forms an image 0.3 m from the lens. Find the location of the object.

(3) The distance between the first and 21^{st} bright fringe in a Young’s double experiment was found to be 2.7 mm. The slit separation was 1.00 mm and the distance from the slits to the plane of the fringes was 25 cm, what was the wavelength of the light?

The fringes are equally spaced

(4) A screen is placed at a distance of 40 cm from a narrow slit illuminated by a parallel beam of monochromatic light of wavelength 5.895 x 10^{-6} m. Calculate the width of the slit if the first dark line lies 0.2 cm on either side of the central maxima.

(5)A plane transmission grating having 6000 lines/cm is used to obtain a spectrum of light from a sodium lamp in the second order. calculate the angular separation between two sodium lines whose wavelength are 6 x 10^{-7} m and 6.05 x 10^{-7} m.

## 1 Comment(s)

#NEWWOL l(Thu, 30th Mar 2023, 12:07 AM)clear workings thanks

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