Which of the following is NOT a basic requirement for chemically based life?
A) a liquid medium to transport biological molecules
B) a source of molecules from which to build living cells
C) oxygen from photosynthesis
D) a source of energy to fuel metabolism
Question 2The capacitive reactance of a capacitor is very small at low frequencies.
Indicate whether the statement is true or false
Question 3The minimum current that will usually kill the average person is
A) 10. A.
B) 0.1 A.
C) 1. A.
D) 0.01 A.
E) 0.1 mA.
Question 4A girl throws a stone straight down from a bridge. The stone leaves her hand with speed of 8.00 m/s at a height of 12 m above the water below. How much time does it take for the stone to hit the water?
A) 2.58 s
B) 0.95 s
C) 1.8 s
D) 0.41 s
E) 17.3 s
Question 5The charge carried by one electron is e = -1.6 10-19 C. The number of excess electrons necessary to produce a charge of 1.0 C is
A) 6.3 1018.
B) 1.6 1019.
C) 6.3 109.
D) 6.3 106.
E) 1.6 1018.
Question 6One of the most efficient engines built so far has the following characteristics: combustion chamber temperature = 1900C; exhaust temperature = 430C. 7 109 cal of fuel produces 1.4 1010 J of work in one hour.
(a) What is the actual efficiency of this engine?
(b) What is the Carnot efficiency of this engine?
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