About how hot was the Big Bang when matter and energy "decoupled"?
A) 900 million K
B) 15 million K
C) 3,000 K
D) 300 K
E) 2.73 K
C
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The process in which a gas cools and its molecules stick together to form liquid particles is called
A. depression. B. sublimation. C. condensation. D. evaporation.
If 50 g of material at 100°C is mixed with 100 g of water at 0°C, the final temperature is 40°C. What is the specific heat of the material?
A) 0.33 kcal/kg ? °C B) 0.75 kcal/kg ? °C C) 1.33 kcal/kg ? °C D) 7.5 kcal/kg ? °C E) 33 kcal/kg ? °C
A 200-loop coil of cross sectional area 8.5 cm2 lies in the plane of the page. An external magnetic field of 0.060 T is directed out of the plane of the page. The external field decreases to 0.020 T in 12 milliseconds
(a) What is the magnitude of the change in the external magnetic flux enclosed by the coil? (b) What is the magnitude of the average voltage induced in the coil as the external flux is changing? (c) If the coil has a resistance of 4.0 ohms, what is the magnitude of the average current in the coil?
The energy differences in some of the rotational energy levels of the water molecule allow
a. X-rays to be produced. b. cooking with microwaves. c. visible spectral lines to be formed. d. lasers to operate.