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:
The frequency will decrease because the waves are getting farther and farther apart and if they and as that happens with shorter and shorter so they decrease
The answer is D. hope I was right
Answer:
904.014 j/kgk
Explanation:
Mass of metal = 45g
Temperature of metal = 85.6°
Mass of water = 150
Temperature of water = 24.6
Final temperature of system = 28.3
Heat lost by metal = Heat gained by water
m1 * c1 * dt = m2 * c2 * dt
Q = quantity of heat
Q = m*c*dt
dt = change in temperature
dt of water = 28.3 - 24.6 = 3.7
dt of metal = 85.6 - 28.3 = 57.3
Specific heat capacity of water, c = 4200
(45 * 10^-3) * c * 57.3 = (150 * 10^-3) * 4200 * 3.7
2.5785c1 = 2331
c1 = 2331 / 2.5785
= 904.01396
= 904.014 j/kgk
