What direct evidence do we have that the weak and electromagnetic forces were once unified as a single electroweak force?
A) The most advanced telescopes are able to see back to this era in the universe.
B) Detectors on Earth have received photons and high-energy particles from this era.
C) Temperatures in the center of the Sun can reproduce the conditions during this era.
D) Particle accelerators on Earth can reach energies equivalent to the high temperatures of this era and have produced particles predicted by the electroweak theory.
E) We have no direct evidence of the electroweak force.
D
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The ignition of helium in the core of a star changes the structure of the star. The star now makes energy in two locations by two different processes, _____
A) carbon fusion in the core and helium fusion in the surrounding shell B) helium fusion in the core and nitrogen fusion in the surrounding shell C) helium fusion in the core and hydrogen fusion in the surrounding shell D) nitrogen fusion in the core and helium fusion in the surrounding shell
Suppose that the tail for a solution to the Schrödinger equation for a given potential energy function is longer in a given classically forbidden region when the energy is EA than that for a solution for energy EB. This means that
A. EA > EB. B. EA < EB. C. It is impossible to tell from the information provided.
The escape velocity for a 100-kg object on Earth is about 11 km/s. What is the escape velocity of a 50-kg object on the surface of Earth?
A) 11 km/s B) 22 km/s C) 5.5 km/s D) 44 km/s E) 2.75 km/s
Two isotopes of uranium have the same
a. mass number b. neutron number c. atomic number d. nucleon number e. nucleon number and neutron number