A circular loop, of loop radius λ/30 and wire radius λ/1000, is used as a transmitting/receiving antenna in a back-pack radio communication system at 10 MHz. The wire of the loop is made of copper with a conductivity of 5 .7 × 10 7 S/m. Assuming the antenna is radiating in free space, determine the:

(a) radiation resistance of the loop;
(b) loss resistance of the loop (assume that its value is the same as if the wire were straight);
(c) input resistance;

On a average work day more than work place firs are reorted

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Determine whether or not it is possible to compress air adiabatically from k to 140 kpa and 400 k. what is the entropy change during this process?