Briefly discuss: (i) the principles of detecting thermal neutrons utilizing a si detector. (ii) the physics of fast neutron detection. (iii) the principle of operation of strip detectors for charged particle detection and their application.

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.

The answer is that they are composed mostly of liquid water.