Question

very massive black holes with masses of Billions of solar masses are primarily formed how?

	A.	They have formed from a collapse of a giant gas cloud
	B.	They are primarily formed through accretion of matter
	C.	The are primarily formed through merging of smaller black holes.
	D.	They have been formed during the Big Bang

What properties of a Black Hole can you determine theoretically

	1.	Mass, magnetic field, and spin
	2.	Mass, Spin, and electric charge
	3.	Mass, chemical composition, Spin
	4.	Spin, magnetic field, and chemical composition.

What can you say about Hawking radiation?

	1.	Hawking radiation can only be seen from super-massive Black holes
	2.	The more massive the black hole the later the luminosity through Hawking radiation
	3.	The smaller the mass of the black hole the more luminous is the Hawking radiation
	4.	You can see Hawking radiation only n the infrared

What is the engine in an AGN

	1.	Splitting of Uranium atoms
	2.	Nuclear fusion of Carbon
	3.	An Accretion Disk around a central Black Hole
	4.	Hawking radiation

Answer 1

1) The scientist are still not sure on how super massive black holes were formed.

But the most accepted theory is that they formed in the early universe by the collapse of super massive gas clouds.

So, the most correct option is Option A

2) The mass of a black hole can be determined theoretically based on the bending of light near it.

The other fundamental properties of a black hole, namely the spin and the charge can also be predicted theoretically.

The internal composition can not be predicted.

So, option B is correct

3) All black holes are supposed to emit hawking radiation.

The luminosity of radiation depends on temperature of a black hole. he temperature is inversely related to mass. So, massive black holes will have less luminosity.

The temperature of balck hole is very less and not in the IR region.

So, the options A, B and D is wrong

Option C is correct

4) AGN is the region in the center of galaxy. The radiation from AGN is due to the accretion of matter by a super massive black hole.

Option C is correct.