The figure above shows the geological time scale of Earth. The K-T event that marks the extinction of the dinosaurs occurred approximately ________ years ago.
A) 65 million
B) 10 million
C) 650 million
D) 100 million
A) 65 million
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A brass plate with a thickness of 1.00 cm is placed over a copper plate with a thickness of 2.00 cm. The coefficient of thermal conductivity of brass is 100 W/m 
and of copper is 400 W/m 
What is the effective coefficient of thermal conductivity for the brass-copper layer?
A. 150 W/m 
B. 200 W/m
C. 250 W/m
D. 300 W/m
E. 350 W/m
The size of a star's image in a photo tells you how _______________ the star appears
Fill in the blank(s) with correct word
The ground state electronic configuration for silicon is 1s22s22p63s23p2 . Which of the following elements would be expected to be chemically similar to silicon?
a. boron with configuration 1s22s22p1 b. lithium with configuration 1s22s1 c. carbon with configuration 1s22s22p2 d. sodium with configuration 1s22s22p63s1
A heat pump is capable of delivering more energy to the home than goes into the operation of the pump itself, when conditions are favorable. Which of the following statements is correct?
A. A heat pump violates the first law of thermodynamics B. A heat pump, like the Carnot engine, is a theoretical device that is not useful in practice C. A heat pump is more efficient when the outside temperature is colder D. A heat pump violates the second law of thermodynamics E. A heat pump transfers some energy from the outdoors