Consider three galaxies, Alpha, Beta and Gamma. An astronomer in Beta sees each of the other two galaxies moving away from her in opposite directions at 0.70c
At what speed would an observer in Alpha see the galaxy Beta moving?
A) 0.82c
B) 0.70c
C) 0.94c
D) 0.35c
E) 0.57c
B
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How much electrical charge does an atom with 6 protons, 6 neutrons, and 5 electrons have?
A) a total charge of +17 B) a negative charge of -5 C) a positive charge of +7 D) a positive charge of +1 E) none of the above
An ideal diode in an ac circuit
A. doubles the current. B. halves the current. C. permits the current to flow in only one direction. D. permits the current to flow in one direction and double the current to flow in the other. E. permits the current to flow in one direction and half the current to flow in the other.
A voltage DV is applied across the ends of a Nichrome heater wire having a cross-sectional area A and length L. The same voltage is applied across the ends of a second Nichrome heater wire having a cross-sectional area A and length 2L. Which wire gets hotter?
1.The shorter wire does. 2.The longer wire does. 3.More information is needed.
Visible light consists of electromagnetic waves with wavelengths (in air) in the range 400 - 700 nm. What are the frequencies of visible light?
a. 
b. 
c. 
d. 