Which of the following statements about open clusters is true?
A) All stars in the cluster will evolve similarly.
B) All stars in the cluster have approximately the same mass.
C) All stars in the cluster are approximately the same color.
D) There is an approximately equal number of all types of stars in the cluster.
E) All stars in the cluster are approximately the same age.
E
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An electron gun sends electrons through a region with an electric field of 
for a distance of 2.5 cm. If the electrons start from rest, how long does it take for the electrons to traverse the gun?
A. 1.1 ns B. 1.1 ?s C. 2.2 ns D. 2.2 ?s E. 4.4 ns
Circular Motion of Charges: A proton, starting from rest, accelerates through a potential difference of 1.0 kV and then moves into a magnetic field of 0.040 T at a right angle to the field. What is the radius of the proton's resulting orbit? (e = 1.60 × 10-19 C, mproton = 1.67 × 10-27 kg)
A. 0.080 m B. 0.11 m C. 0.14 m D. 0.17 m
The habitable zones for stars may be considerably larger if they have planetary systems containing
A) super-Earths with thick hydrogen atmospheres B) Earth-sized planets with thick carbon dioxide atmospheres C) super-Earths with thin hydrogen atmospheres D) Earth-sized planets with thick methane atmospheres
An alternating current circuit has resistance R, inductance L, and capacitance C in series with a voltage source. Which statement is correct?
A. The voltage across the capacitor leads the voltage across the inductor by 90°. B. The voltage across the inductor leads the voltage across the capacitor by 90°. C. The voltage across the inductor leads the voltage across the resistor by 180°. D. The voltage across the inductor is out of phase with the voltage across the capacitor by 180°. E. Both voltages lead the voltage across the resistor by 90°.