Suppose someone tells you that the Sun generates its light and heat because it is a giant ball of fire. Would you agree? Why or why not?
What will be an ideal response?
Answer: No. Fire is produced by chemical burning. The Sun could not possibly have generated chemical energy for billions of years because this process would have burned itself out long ago. The correct explanation is that the Sun generates its light and heat from nuclear fusion in its core.
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A 100-g block of copper is taken from a kiln and quickly placed into a beaker of negligible heat capacity containing 300 g of water. The water temperature rises from 15°C to 40°C. Given cCu = 0.10 cal/g•°C, and cwater = 1.00 cal/g•°C, what was the temperature of the kiln?
a. 500°C c. 790°C b. 635°C d. 535°C
A straight wire is bent into the shape shown. Determine the net magnetic force on the wire when the current I travels in the direction shown in the magnetic field 
.
a.
2IBL in the ?z direction
b.
2IBL in the +z direction
c.
4IBL in the +z direction
d.
4IBL in the ?z direction
e.
zero
You can hear sound through an open window from sources that are not in your line of sight because of __________
Fill in the blank(s) with correct word
Intensity of Sound: A certain glass window reduces the intensity level of the sound from 72 dB to 47 dB. By what factor is the acoustic power reduced by this glass window?
A. 3.2 × 10-3 B. 2.2 × 10-2 C. 5.6 × 10-2 D. 1.0 × 10-1 E. 1.5 × 10-1