This figure shows the Cepheid period-luminosity relation. Suppose that a Cepheid with a period of 30 days has the same apparent brightness as a nearby star with a luminosity identical to our Sun. How many times farther away is the Cepheid? (Hint: First use the graph to find the Cepheid's luminosity, then apply the inverse square law for light.)
A) The Cepheid is 10 times farther away than the nearby star.
B) The Cepheid is 100 times farther away than the nearby star.
C) The Cepheid is 10,000 times farther away than the nearby star.
D) The Cepheid is actually 10 times closer than the nearby star.
B) The Cepheid is 100 times farther away than the nearby star.
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How much heat must be removed from 456 g of water at 25.0°C to change it into ice at -10.0°C? The specific heat of ice is 2090 J/kg ? K, the latent heat of fusion of water is 33.5 × 104 J/kg, and the specific heat of water is 4186 J/kg ? K
A) 105 kJ B) 153 kJ C) 57.3 kJ D) 47.7 kJ E) 210 kJ
A particle (q = 4.0 mC, m = 50 g) has a velocity of 25 m/s in the positive x direction when it first enters a region where the electric field is uniform (60 N/C in the positive y direction). What is the speed of the particle 5.0 s after it enters this region?
A. 49 m/s B. 35 m/s C. 32 m/s D. 44 m/s E. 24 m/s
Explain why cars are responsible for so much of the carbon monoxide emitted every year (see Table 15.5)
What will be an ideal response?
Two harmonic waves are described by 
What is the magnitude of the speed (in m/s) of the two traveling waves?
A. 16 B. 4.0 C. 8.0 D. 0.25 E. 2.0