A coil is placed in a magnetic field and has a flux ?B through it. The coil is stressed so that its area reduces to 75% of its original value. If the plane of the coil stays the same and the flux through it remains the same, how must the magnetic field change?
a. It must increase by 25%.
b. It must increase by 33%.
c. It must increase by 125%.
d. It must decrease by 25%.
b
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When charges qa, qb, and qc are placed respectively at the corners a, b, and c of a right triangle, the potential at the midpoint of the hypotenuse is 20 V. When the charge qa is removed, the potential at the midpoint becomes 15 V. When, instead, the charge qb is removed (qa and qc both in place), the potential at the midpoint becomes 13 V. What is the potential at the midpoint if both charges qa
and qc are removed? a. 13 V c. 5 V b. 7 V d. 8 V
In the context of the behavior of black holes, briefly explain the concept of time dilation
What will be an ideal response?
What clues do other Kuiper belt comets offer about the origin of the belt?
A. The similar characteristics of Kuiper belt objects such as travel direction, orbit inclination, stable orbital resonance with Neptune, and composition suggest that these objects have the common origin and were formed in the outer region of the solar system. B. The similar characteristics of Kuiper belt objects such as travel direction, orbit inclination, stable orbital resonance with Jupiter, and composition suggest that these objects were formed in the inner region of the solar system and than draged to the farther distance. C. Kuiper belt objects have different travel direction, orbit inclination, and composition. They also do not have orbital resonances with any of the planets. It suggest that these objects were formed outside the solar system and than attracted by the gravity of the Sun and jovian planets. D. Kuiper belt objects have different travel direction, orbit inclination, and composition. They also have orbital resonances with different jovian planets. It suggest that these objects were formed in different regions of the solar system and than draged to their present orbits.
Why are star clusters almost ideal "laboratories" for stellar studies?
A) All stars in the cluster are the same size and luminosity. B) Their combined light makes them much easier to spot from a distance. C) Stars in clusters have the same age, similar composition, and are at the same distance away. D) Stars in clusters are all relatively young and therefore shine brightly. E) Like our Sun, stars in clusters are always located in the plane of the Milky Way Galaxy.