Section A
Q1.
(a) Describe the principle of radioactive decay. Draw schematically the decay of parent nuclides and growth of daughter nuclides. What is the relationship between half-life and decay constant.
(b) State radioactive equilibrium. Describe the equations representing α emission, β emission and K capture.
(c) What is the predominant noise that appears in marine seismic records and how to reduce it.
(d) Schematically draw the nature of waveforms of airgun and swept-frequency seismic sources.
(e) A continuous time signal x(t) is obtained at the output of an ideal low-pass filter with cutoff frequency ω_c = 2 × 103 π rad/sec. If the impulse train sampling is performed on signal x(t), with sampling periods of (i) 2 × 10-4 sec and (ii) 2 × 10-3 sec then which sampling period will recover the signal from its sampled version using an appropriate low-pass filter.
(f) Define discrete even and odd signals with graphical illustrations.
(g) Write about the hazards associated in coastal aquifers when excess water is drawn.
(h) What is the significance of thermal sensors in Remote Sensing ?
