Redshift caused by this phenomenon was observed in the Pound-Rebka experiment. For 10 points each:
[10m] Name this phenomenon, described in one theory as a geometric property of spacetime. The Twin Quasar appears as two images because of this phenomenon’s namesake lensing.
ANSWER: gravity [accept gravitational redshift or gravitational lensing]
[10e] Gravity is described as a geometric property of spacetime in this theory published by Albert Einstein. This theory was published 10 years after a related "special" version.
ANSWER: general relativity [prompt on relativity]
[10h] General relativity was influenced by this statement, which states inertial and gravitational mass are the same. A strong form of this statement says experiments will give the same results in all locally inertial reference frames.
ANSWER: equivalence principle [accept strong equivalence principle; accept Einstein’s equivalence principle]
<Physics>