Punjab Engineering College 2010 B.E Engineering Physics Py101 mid-term - Question Paper
//THE ques. PAPER IS OF MID-TERM exam PY101 COURSE P.E.C.//
TIME: one HOUR
(Do not write anything else on the question Paper)
Mid Term Test 1 Feb 2010
SID:__
PY -101 PHYSICS -1
Attempt all questions Time allowed: lHour Max. Marks: 6 x 5 = 30
Ql. A radar antenna is located atop a high cliff on the edge of a lake operates at a wavelength of 400 m. A parallel beam of electromagnetic wave is received by the antenna at E. one ray CE directly comes to E and the other along the path ABE (after reflection at the water surface) the first minimum is recorded when the angle ABF = 35. Find the height of the cliff.
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Q2. We wish to coat a flat glass (\i =1.5) with a transparent material (n =1.38) to reduce the reflection. What is the minimum thickness required for coating the glass surface to reduce the reflection at 600 nm, assuming the normal reflection?
Q3. In Newton's ring experiment prove that the difference in radius between adjacent bright
rings is given by - I , when n 1. Also show that the area between adjacent ring is given by nX R (when n 1).
Q4. A light of wavelength 600 nm falls on a grating having 5000 lines per cm. What is the highest order spectrum may be observed? If the opaque spaces of the grating are equal to the transparent spaces then what will happen to the spectrum?
Q5. A plane polarized light of wavelength 500 nm falls on a calcite plate cut with faces parallel to optic axis. Find the ratio of intensities of O-ray and E-ray, if the plane of vibration makes an angle of 30 with the optic axis of the crystal. Also find the minimum thickness of the plate which introduces a phase difference of 60 between O-ray and E-ray. (\i0 = 1.544, ne=1.553 )
Q6. For a grating with grating element (a+b) = 18000A. Calculate the dispersive powers in the first and third order spectra around X- 5000 A, assuming normal incidence.
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| Earning: Approval pending. |
