Consider a bare fiber having n_1 = 1\cdot 48 and n_2 = 1\text{ (air)}. Find out the NA. What is the maximum incident angle up to which light can be guided through the fiber?
ifos-2010-subject-02-010
(ii) Why are the two wavelengths 1\cdot 30\ \mu\text{m} and 1\cdot 55\ \mu\text{m} important in single-mode fiber-optical communication system?
ifos-2010-subject-02-005
(i) Between multimode and single-mode fibers, explain critically how and why single-mode fiber is chosen for communication.
ifos-2010-subject-02-004
A slit 0\cdot 25\text{ mm} wide is placed in front of a convex lens and illuminated by plane waves of wavelength 500\text{ nm}. The Fraunhofer diffraction pattern is formed in the focal plane of the lens. In the pattern, the distance from the third minimum on the left to the third minimum on the right is found to be 3\text{ mm}. Find the focal length of the lens.
ifos-2010-subject-02-003
(ii) Determine its quality factor Q and width of resonance \Delta f.
ifos-2010-subject-02-001
(i) An electron of rest mass m_0 moves with a velocity v such that its total energy is double of its rest mass energy. What is the electron velocity?
ifos-2010-subject-01-007
(i) For a particle of mass m moving with velocities \vec{v}_s and \vec{v}_r relative to the space and rotating axis, respectively, show that the equation of motion is obtained as \vec{F}-2m(\vec{\omega}\times\vec{v}_r)-m\vec{\omega}\times(\vec{\omega}\times\vec{r}) = m\vec{a}_r with \vec{\omega} and \vec{a}_r being the angular velocity and acceleration in rotating coordinates.
ifos-2010-subject-01-006
Show that the magnitudes of the centripetal and Coriolis accelerations of the earth while rotating counter-clockwise about the north pole are around 0\cdot 034\text{ m sec}^{-2} and (1\cdot 46 \times 10^{-4} v)\text{ m sec}^{-2}, respectively. In obtaining these results, consider the ratio of sidereal days to solar days in a year as (366\cdot 5/365\cdot 5) and the radius of the earth along the equator as 6400\text{ km}.
ifos-2010-subject-01-005
(iii) Discuss the important role of Coriolis forces in the circulation pattern of winds.
ifos-2010-subject-01-004
(ii) Which term in the above equation represents the Coriolis force?
ifos-2010-subject-01-003
How can one introduce the constraints of motion through the concept of generalized coordinate systems? Write down the set of transformation equations for a system of N particles relating the generalized coordinates with the real coordinates.
ifos-2010-subject-01-002
Establish the relation between the angular momentum and torque of a particle. Show that this relation leads one to the principle of conservation of angular momentum.
ifos-2010-subject-01-001
(ii) At what velocity, the electron momentum will be m_0 c?
ifos-2010-subject-01-008