A simple magnifier of refractive power 15.0 D is used to observe a beetle on a student’s desk. If the image of the beetle is formed at her nearpoint of 25 cm, how far is the beetle from the magnifier?
A. 50 cm
B. 6.3 cm
C. 4.2 cm
D. 17 cm
C. 4.2 cm
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An empty spice bottle has an inner volume of 1.31 × 10^-4 m3 . It has a mass of 112 g when filled with air, and it displaces 1.63 × 10^-4 m3 of water when fully submerged. What fraction of the total volume of the bottle will be beneath the surface when it is placed in a tank of water?
a. 0.69 b. 0.81 c. 0.85 d. 1.00 e. 1.46
Which dominated Galileo's method of extending knowledge: Philosophical discussion or experiment?
Algol consists of a 3.7 MSun main-sequence star and a 0.8 MSun subgiant. Why does this seem surprising, at least at first?
A) A star with a mass of 3.7 MSun is too big to be a main sequence star. B) The two stars should be the same age, so we'd expect the subgiant to be more massive than the main-sequence star. C) It doesn't make sense to find a subgiant in a binary star system. D) The two stars in a binary system should both be at the same stage of life; that is, they should either both be main sequence stars or both be subgiants.
Which of the following statements is true of Jupiter?
A) It is more than 5.5 times denser than water. B) The interior of Jupiter is mostly liquid helium. C) The rocky core at Jupiter's center contains light elements. D) It has a slightly flattened shape.