Answer:
every method of removing heat from LED's should be considered. Conduction, convection, and radiation are the three means of heat transfer. Typically, LED's are encapsulated in a transparent resin, which is a poor thermal conductor. Nearly all heat produced is conducted through the back side of the chip. Heat is generated from the PN junction by electrical energy that was not converted to useful light, and conducted to outside ambiance through a long path, from junction to solder point, solder point to board, and board to the heat sink and then to the atmosphere. A typical LED side view and its thermal model are shown in the figures.
Explanation:
Answer:
13. c) Net
14. a) Gravity
15. d) Watt
16. b) the speed will suddenly decrease.
Explanation:
13. The <u>net </u> force is combination of all individual forces.
14. When we sit on the chair , then <u>gravitational force</u> acts on our body due to our mass.
F = mg
here, F = force due to gravity , g = acceleration due to gravity and m= mass of the body
15.Power : It is the force acting per unit area .It is discovered by James Watt
Its unit is 
.In honor of the Scientist , its unit is Watt.
Watt =
16. When the parachute first opens , the <u>speed of the skydiver suddenly decreases</u> because of the resistance offered by the air particles.(For more details look at the figure attached)
17. Transfer of momentum from one object to other is t<u>he law of conservation of momentum</u><u> </u>(NOT ENERGY).So the answer is<u> </u><u>False</u>
<u> Law of Conservation of Momentum : </u> Total momentum of a system is conserved if no external force attack on it. Momentum can neither be created nor destroyed but transferred from one form to other.
Elements that belong to the same group in the periodic table will have similar chemical properties. This occurs because same group elements have the same number of electrons in its outer shell. Molybdenum will have the most properties in common with the element Chromium as they are both in the same group on the periodic table.
In longitudinal waves, the oscillations are along the same direction as the direction of travel and energy transfer.
Sound waves and waves in a stretched spring are longitudinal waves. P waves (relatively fast moving longitudinal seismic waves that travel through liquids and solids) are also longitudinal waves.
Longitudinal waves show area of compression and rarefaction. In the animation, the areas of compression are where the parts of the spring are close together, while the areas of rarefaction are where they are far apart.
