A laser cannot emit more energy than is put into it. But in instances where stored energy can be released in a very short time, the laser
A) puts out more energy than is put into it.
B) has a greater power output than power input.
C) both of these
D) neither of these
Answer: B
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In Part A, you found that Earth emits only infrared light. This infrared light can be absorbed by greenhouse gases, such as carbon dioxide and water vapor, in the atmosphere. In fact, all the terrestrial planets emit infrared light from their surfaces. The following images show the four terrestrial planets in our solar system. Rank these planets from left to right based on the total amount of infrared-absorbing greenhouse gases in their atmospheres, from greatest to least.
A solid sphere, a solid cylinder, a spherical shell, and a hoop all have the same mass and radius. Each are rolling on a horizontal surface with the same center of mass speed, and then they roll up identical inclines. Which one goes the greatest distance up its incline?
a. the hoop b. the solid sphere c. the spherical shell d. the cylinder e. They all go the same distance up their inclines.
A 2.0-m wire carries a current of 15 A directed along the positive x axis in a region where the magnetic field is uniform and given by B = (30? 40
) mT. What is the resulting magnetic force on the wire?
A.
B.
C.
D.
E.
A spherical conductor of radius 2.0 mm carries a charge of 7.1 nC. What is the magnitude of the electrical field at 6.0 mm from the center of the sphere? (k = 1/4??0 = 9.0 × 109 N ? m2/C2 )
A) 89 × 106 N/C B) 25× 106 N/C C) 1.8 × 106 N/C D) 780 × 106 N/C E) 0.89 × 106 N/C