Question

Question 1 (1 point) What explanation does general relativity provide for gravity? A) Gravity can affect only massive particles, not massless photons B) Gravity is inversely proportion to the radius of the body. c) Gravity is directly proportional to the mass of the attracting body. D) Gravity is the opposite of the electromagnetic force. OE) Gravity is the result of curved spacetime. Question 2 (1 point) If light from a distant star passes close to a massive body, the light beam will A) continue moving in a straight line. B) change color to a shorter wavelength. C) bend towards the star due to gravity. D) slow down. E) accelerate due to gravity.

Answer 1

1.E)Gravity is a result of curved space time.As we know from Einstein's General Theory of Relativity that Gravity represents Geometry of space time from a mathematical point of view.If we little bit study Einstein's famous field equation .we can see that gravity is nothing but is a result of curved space time.

.2.C) Bend towards the star due to gravity.As we know from General Theory Of Relativity that a massive mass body curved its local space time,that's why any test mass passing near the massive body will go through this curved space time and bend towards the massive body due to gravity.

3.E) Nothing.Any matter that has crossed the event horizon ,we can not detect or say nothing about it ,what will happen to it.Because any matter even light cannot escape from event horizon .

4.E)All of above.From point of view of General theory of gravity any things which has mass can be affected by gravity,because gravity only concerns about mass,as we know photons have also tiny but nonzero mass ,that's why along with others it will also affected due to gravity.

5. If the sun is replaced by one solar mass of black hole,nothing will changes immediately .Because extreme gravitational pull of black hole ,it will pull earth and also its nearby planets towards it and planets will start drifting towards black hole, will vanish completely in couples of years.

6.E)The system must be very strong source of radio emission,because if in a binary system there is one black hole,then it will pull its companion mass slowly ,due to its extreme gravitational pull.During this process black hole ejects not only radio but also X-ray,gamma ray emission.After investigate these emission from the data of different satellite  ,we can say that there is a black hole.

7.B)The mass of the visible companion is even greater than the mass Cygnus-X-1,at around 25 solar masses.Because its range is 5 to 10 solar masses.