Which of the following is not a name used in the classification of galaxies?
a. Irregular
b. Regular
c. Spiral
d. Elliptical
b
You might also like to view...
Force on a Moving Charge: Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. What are the signs of the charges of these three particles?
A. 1 is neutral, 2 is negative, and 3 is positive. B. 1 is neutral, 2 is positive, and 3 is negative. C. 1 is positive, 2 is neutral, and 3 is negative. D. 1 is positive, 2 is negative, and 3 is neutral. E. 1 is negative, 2 is neutral, and 3 is positive.
If an AC circuit consists of a 220 mH inductor in series with a 25 pF capacitor and an AC generator with rms voltage of 12 V. At what frequency will the rms voltage drop across the capacitor be equal to that across the inductor?
A. 94 kHz B. 15 kHz C. 68 kHz D. 426 kHz
A series LR circuit includes a 9.0 V battery, a resistance of 0.50 
and an inductance of 0.80 H. What is the current 2.0 s after the switch is closed?
A. 18 A B. 13 A C. 6.4 A D. 5.2 A E. 4.3 A
Exclusion Principle: According to the quantum mechanical model of the hydrogen atom, if the orbital angular momentum quantum number is ?, there will be how many permitted magnetic quantum numbers?
A. ?/2 B. 2? C. 2? + 1 D. 2? - 1 E. 3?