Which of the following is the most similar, in its operation, to a photovoltaic cell?
A) fluorescent light bulb
B) geothermal energy
C) fossil-fuel electric power plant
D) battery
E) automobile engine
Question 2
If an x-ray beam of wavelength 1.4 10-10 m makes an angle of 20 with a set of planes in a crystal causing first order constructive interference, at what angle will the second order line appear?
A) 40
B) 20
C) 43
D) 4.0
E) 11