Uranium-238 decays into lead-206 with a half-life of 4.5 billion years. Suppose you found a rock in which only 1/4 of the original uranium-238 remained (the other ¾ having become lead-206). How old would the rock be?
A) 9 billion years
B) 4.5 billion years
C) 2.25 billion years
D) 13.5 billion years
A) 9 billion years
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Ideal Gas Law: Your lungs hold 4.2 L of air at a temperature of 27°C and a pressure of 101.3 kPa. How many moles of air do your lungs hold? (R = 8.31 J/mol ? K)
A. 0.15 moles B. 0.17 moles C. 0.19 moles D. 0.21 moles E. 0.23 moles
According to the text’s final model (including the ocean effect), about when will the earth’s average surface temperature be 288.4 K?
A. 2015 B. 2030 C. 2045 D. Some other date (specify)
Two steel wires are stretched with the same tension. The first wire has a diameter of 0.610 mm and the second wire has a diameter of 0.910 mm
If the speed of waves traveling along the first wire is 54.0 m/s, what is the speed of waves traveling along the second wire? A) 24.9 m/s B) 27.2 m/s C) 36.2 m/s D) 81.0 m/s E) 100 m/s
A rad is that amount of radiation that:
a. is also known as a rem. b. deposits 10–2 J of energy into 1 kg of absorbing material. c. deposits 8.76 × 10^–3 J of energy into 1 kg of air. d. produces 2.08 × 10^9 ion pairs per cm3 in air under standard conditions.