If the external force parallel to contact surface exceeds maximum static friction, then the body starts moving over underlying surface. It does not mean, however, that friction between surfaces disappears. New contact points between surfaces come in contact, some of which are momentarily joined and then broken on continuous basis. The friction force is dropped slightly (almost instantly); but remains constant - independent of the velocity of the body.

We denote kinetic friction force as F_k and corresponding friction coefficient as μ_k . The kinetic friction is related to normal force

CHCl3 (1) reacts with strong base to form the chloroform carbanion (2), which will quickly alpha-eliminate to give dichlorocarbene (3). Dichlorocarbene will react in the ortho- and para- position of the phenate (5) to give the dichloromethyl substituted phenol (7). After basic hydrolysis, the desired product (9) is formed.

          GEOMETRICAL OPTICS

1. Real images are always inverted.




2. Virtual images are always upright.




3. Diverging lens (concave) produce only small virtual images.




4. Light rays bend away from the normal as they gain speed and a longer wavelength by entering a slower (n) medium {frequency remains constant}.




5. The focal length of a converging lens (convex) is shorter with a higher (n) value lens or if blue light replaces red.
   
   MODERN PHYSICS
   
   
   
   


6. The particle behavior of light is proven by the photoelectric effect.


7.  


8. A photon is a particle of light {wave packet}.




9. Large objects have very short wavelengths when moving and thus can not be observed behaving as a wave. (DeBroglie Waves)




10. All electromagnetic waves originate from accelerating charged particles.




11. The frequency of a light wave determines its energy (E = hf).




12. The lowest energy state of a atom is called the ground state.




13. Increasing light frequency increases the kinetic energy of the emitted photo-electrons.




14. As the threshold frequency increase for a photo-cell (photo emissive material) the work function also increases.




15. Increasing light intensity increases the number of emitted photo-electrons but not their KE.
    
    INTERNAL ENERGY
    
    
    


16. Internal energy is the sum of temperature (ke) and phase (pe) conditions.




17. Steam and liquid water molecules at 100 degrees have equal kinetic energies.




18. Degrees Kelvin (absolute temp.) Is equal to zero (0) degrees Celsius.




19. Temperature measures the average kinetic energy of the molecules.




20. Phase changes are due to potential energy changes.




21. Internal energy always flows from an object at higher temperature to one of lower temperature.
    
    NUCLEAR PHYSICS
    
    
    


22. The atomic number is equal to the number of protons (2 for alpha)




23. Deuterium () is an isotope of hydrogen ()




24. The number of nucleons is equal to protons + neutrons (4 for alpha)




25. Only charged particles can be accelerated in a particle accelerator such as a cyclotron or Van Der Graaf generator.




26. Natural radiation is alpha (), beta () and gamma (high energy x-rays)




27. A loss of a beta particle results in an increase in atomic number.




28. All nuclei weigh less than their parts. This mass defect is converted into binding energy. (E=mc²)




29. Isotopes have different neutron numbers and atomic masses but the same number of protons (atomic numbers).




30. Geiger counters, photographic plates, cloud and b




31. Alpha particles are the same as helium nuclei and have the symbol .




32. Bubble chambers are all used to detect or observe radiation.




33. Rutherford discovered the positive nucleus using his famous gold-foil experiment.




34. Fusion requires that hydrogen be combined to make helium.




35. Fission requires that a neutron causes uranium to be split into middle size atoms and produce extra neutrons.




36. Radioactive half-lives can not be changed by heat or pressure.




37. One AMU of mass is equal to 931 meV of energy (E = mc²).




38. Nuclear forces are strong and short ranged.
    
    
    
    COMMENT IF USEFUL@@@@@@

The transformer is not a power source. It functions like a lever to convert a small voltage pushing a large electric current into a large voltage pushing a small electric current or vice versa. The power in an electric circuit is equal to the voltage multiplied by the current. For a perfect transformer, all the power that enters comes back out. If the transformer is not perfect, a portion of the power that enters is converted to heat.

The transformer is intended for use only with an alternating current while the current induced in the power lines as a result of space weather disturbances is a direct current. The transformer, which usually operates with 99% efficiency, begins to malfunction. Magnetic flux ceases to be concentrated inside the iron core of the transformer and impinges on regions that were not designed to withstand this. Power begins to be converted into heat. The transformer moans and creaks loudly and overheats. Oil fires and melt-down of transformer components can occur. This happens not just to one transformer but at the same time to all affected transformers on the grid. Some transformers may burn up. Others experience significantly shortened lifetimes following damage during magnetic storm events but don't fail outright.

Projectile motion is a special case of two dimensional motion with constant acceleration. Here, force due to gravity moderates linear motion of an object thrown at certain angle to the vertical direction. The resulting acceleration is a constant, which is always directed in vertically downward direction.



The projectile motion emphasizes one important aspect of constant acceleration that even constant acceleration, which is essentially unidirectional, is capable to produce two dimensional motion. The basic reason is that force and initial velocity of the object are not along the same direction. The linear motion of the projected object is continuously worked upon by the gravity, which results in the change of both magnitude and direction of the velocity. A change in direction of the velocity ensures that motion is not one dimensional.

The change in magnitude and direction of the velocity is beautifully managed so that time rate of change in velocity is always directdirected in vertically downward direction i.e. in the direction of gravity

REFER TO LINK http://en.wikipedia.org/wiki/Resistors AND http://www.goiit.com/chapters/tutorial/physics/electric_current.htm