Question

Note: More than one answer can be correct

1.11. Einstein's “Classic” tests proposed in 1915 for general relativity are: 1) Precession of perihelion of Mercury. 2) Light is bent in a gravitational field. 3) Clocks run slow in gravitational field_ ("gravitational time dilation” or “gravitational redshift”). 4) All the above.

Answer 1

Answer :-all of these
.The "Classic" Tests of General Relativity

Precession of Mercury's orbit

• Deflection of starlight gravitational lensing

• Gravitational Time Dilation

• Gravitational Hed Shift

◆Mercury Precession

• Known since 1850's not to match Newtonian theory

- Perihelion precession by 43 arcseconds per year • Would take 30,000 years to go full-circle

• While putting finishing touches on GR in 1915, Einstein computed expected perihelion precession of Mercury

- He got 43 arcsec/year, Imagine that!
◆Deflection of Starlight

• During an eclipse, the sky around the sun is dark enough to see distant stars.

Stars close to the sun have their light deflected and so appear at a shifted position (farther from sun)

Comparing stellar locations with and without the presence of the sun along the line of sight allows for a measurement of the deflection of light rays.
◆Eddington's Eclipse Expedition in 1919 • Eddington was a British astronomer

Eddington decided to go to Principe Island in the Gulf of Guinea for the eclipse

After months of drought, it was pouring rain on the
day of the eclipse The clouds parted just in time for the team to take photographic plates showing the location of stars around the limb of the sun

Analysis of the photographs produced a deflection in agreement with the GR prediction Gravitational Lensing is now a powerful tool in astrophysics
◆Lunar Laser Ranging

Can test Equivalence Principle (universality of free-fall) by pinging moon with laser pulse
GR relies completely on this principle: accelerations Independent of mass-gravity can be "fictitious" force • Test Earth and Moon in free fall toward (around) Sun.