Draw a neat diagram to show how light propagates through a graded index optical fiber from the entrance to the fiber end and explain.
ifos-2014-subject-02-007
Starting with the rate equations for matter-radiation interaction, show that the ratio of the Einstein's A and B coefficients is proportional to the third power of the frequency of radiation.
ifos-2014-subject-02-008
Deduce the minimum energy of a gamma ray photon (in MeV), which can cause electron-positron pair production.
ifos-2014-subject-01-003
State Hamilton's principle for a system of particles. If I and L represent the action integral and the Lagrangian function, respectively, write down the mathematical form of Hamilton's principle and explain clearly the significance of the same.
ifos-2014-subject-01-002
Using the concept of D'Alembert's principle, show that the generalized force can be defined as Q_j = \sum_i \bar{F}_i \cdot \frac{\partial \bar{r}_i}{\partial q_j} , where \bar{r}_i is the Cartesian coordinate of the i^{\text{th}} particle experiencing external force \bar{F}_i and q_j stands for the generalized coordinate. Discuss the significance of the above expression.
ifos-2014-subject-01-001
Derive the law of addition of relativistic velocities. Use it to prove that under the Lorentz transformation no two velocities can add upto more than the value of the speed of light.
ifos-2014-subject-01-006
A particle of rest mass M moving at a velocity u collides with a stationary particle of rest mass m. If the particles stick together, show that the speed of the composite ball is equal to u\alpha M/(\alpha M + m), where \alpha = \frac{1}{\sqrt{1 - \frac{u^2}{c^2}}} .
ifos-2014-subject-01-005
Discuss the torque-free motion of a symmetric rigid body and hence estimate the period of precession of Earth's polar axis. [Use \frac{I_3 - I_1}{I_3} = 0.33, where I_1, I_2 and I_3 are the moments of inertia about the three principal axes of the Earth]
ifos-2014-subject-01-004
Write down London second equation for superconductors. Explain how it accounts for the Meissner effect.
ifos-2013-subject-08-002
Can you comment from the above question whether you can use it to scan surface by microscopy?
ifos-2013-subject-08-001
Prove the following Boolean identity and draw its gates equivalent : Y = \bar{B}(A + C) + C(\bar{A} + B) + AC
ifos-2013-subject-08-005
In an operational amplifier, the amplifier gain is 10000. The input series resistance is 100\text{ k}\Omega and the feedback resistance is 500\text{ k}\Omega. If the input voltage is 1\text{ volt}, find the exact output voltage and percentage error considering an infinite gain for the amplifier.
ifos-2013-subject-08-004
What is a thermistor? Discuss static characteristics of a thermistor. What is its time constant?
ifos-2013-subject-08-003
Write down the quark structure of \pi^0, \pi^+, \text{K}^0 and \text{K}^+ mesons.
ifos-2013-subject-07-006
What is solar neutrino problem and how the phenomenon of neutrino oscillations provides a solution for the problem?
ifos-2013-subject-07-007
Why was neutrino invoked upon by Fermi and how was it placed into experimental evidence?
ifos-2013-subject-07-005
How magnetic moment and electric quadrupole moment of deuteron indicate the presence of non-central forces in deuteron?
ifos-2013-subject-07-004
What is the importance of the study of deuteron? Discuss the problem of ground state of deuteron and elicit information about nuclear forces from this study.
ifos-2013-subject-07-003
How many fissions take place per second in a 300\text{ MW} reactor? Assume that 200\text{ MeV} is the energy released per fission.
ifos-2013-subject-07-002
The masses of hydrogen atom and neutron are 1 \cdot 007825\text{ u} and 1 \cdot 008665\text{ u} respectively. Calculate the binding energy per nucleon of {}^{12}_6\text{C} nucleus.
ifos-2013-subject-07-001