It is unlikely that we will be able to detect the signals from civilizations in other galaxies because
A) signals from other galaxies will be severely weakened by distance, making them far harder for us to detect
B) other galaxies are unlikely to harbor intelligent civilizations
C) signals from civilizations on other galaxies will not reach us before we give up listening
D) they will most likely transmit at wavelengths that will be absorbed by intergalactic gas
Question 2Convection can occur
A) only in gases.
B) only in solids.
C) only in liquids.
D) only in liquids and gases.
E) in solids, liquids, and gases.
Question 3A conductor is placed in an electric field under electrostatic conditions. Which of the following statements is correct for this situation?
A) The electric field is zero inside the conductor.
B) All valence electrons go to the surface of the conductor.
C) The electric field on the surface of the conductor is perpendicular to the surface.
D) All of the other answers apply.
Question 4Compare two vibrating strings, each has the same tension, but the second has four times the mass density of the first. The wave speed along the 2nd string is how many times the speed along the 1st?
A) 1/4
B) 1/2
C) 4
D) 2
E)
Question 5What is the result of adding 23.4 to 91.237 and then subtracting 23.4?
A) 91.237
B) 91.2
C) 91.3
D) 91.0
E) 91.