An electron and positron, each having kinetic energy 10 MeV, annihilate and produce two photons. What wavelength is each photon?

A. 0.124 pm
B. 0.118 pm
C. 0.248 pm
D. 0.062 pm
E. need more information


A. 0.124 pm

Physics & Space Science

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Equation of Traveling Waves: Four waves are described by the following equations, where distances are measured in meters and times in seconds.I. y = 0.12 cos(3x - 21t)II. y = 0.15 sin(6x + 42t)III. y = 0.13 cos(6x + 21t)IV. y = -0.23 sin(3x - 42t)Which of these waves have the same speed?

A. I and II B. I and III C. II and III D. III and IV E. II and IV

Physics & Space Science

The electric field in the region defined by the y-z plane and the positive x axis is given by E = ax, where a is a constant. (There is no field for negative values of x.) As x increases in magnitude, relative to V = 0 at the origin, the electric potential in the region defined above is

A. a decreasing function proportional to ?|x2|. B. a decreasing function proportional to ?|x|. C. constant. D. an increasing function proportional to +|x|. E. an increasing function proportional to +|x2|.

Physics & Space Science

What was special about the Tunguska impact in Siberia on 1908?

A) the object exploded completely before it hit the ground B) the object that hit was a comet and not an asteroid C) the event had been predicted long before it happened D) the impact created the biggest impact crater seen in recorded history

Physics & Space Science

A long solenoid produces a field at its center. An identical solenoid is placed end to end with the first (common axis). The magnetic field at the center of the 1st solenoid is now

A) zero. B) the same. C) double. D) four times the original magnitude. E) half what it was.

Physics & Space Science