About how many galaxies are there in the observable universe?
A) roughly (within about a factor of 10) the same as the number of stars in our galaxy
B) a few dozen
C) a few thousand
D) about as many as the number of grains of sand on all the beaches on Earth
E) an infinite number
A) roughly (within about a factor of 10) the same as the number of stars in our galaxy
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The arrow in the photo on the left points to the location of the star that has exploded as a supernova in the photo on the right. From this photo pair alone, what can we conclude about the star that exploded? (Assume that we know the star was not a member of a binary system.)
A) It was a high-mass star with at least 8 times the mass of the Sun. B) It is now a black hole. C) It was a red giant star. D) Before the supernova, the star lived for at least a billion years.
The second law of thermodynamics leads us to conclude that
A) the total energy of the universe is constant. B) disorder in the universe is increasing with the passage of time. C) it is theoretically possible to convert heat into work with 100% efficiency. D) the average temperature of the universe is increasing with the passage of time.
An alpha particle is like with 2 protons and 2 neutrons, whereas a beta particle is equivalent to hydrogen
a. True b. False Indicate whether the statement is true or false
A force F is exerted on an object of mass m through a distance d. A force twice as large (2F) is exerted on a mass 2m also through the distance d. Explain the relation between the amount of work done in the two cases
What will be an ideal response?