Our sun is not enough to become a black hole. But if it were, and it collapsed, would the Earth be draw into it?

If there were no atmosphere, Earth would have been

If there were no atmosphere, what would be the colour of the Earth?

If the sun were suddenly replaced by a block hole of one solar mass, what would happen to the earth's orbit immediately after the replacement ?

Let the sun contracts due to self-gravity and it becomes a black hole. If the mass of sun is $2\times {10}^{30}$ kg, then possible radius of sun to behave as a black hole is

if the universe were shrunk to the size, of earth, how large would the earth be on this scale?

Number of possible black holes in our galaxy is

A perfectly absobing, black, solid sphere with constant density and radius R, hovers stationary above the sun. This is because the gravitational attraction of the sun is balanced by the pressure due to the sun's light. Assume the sun is far enough away that it closely approximates a point source of light. The distance from the centre of the sun at which the sphere hovers is :

The solar constant is the amount of heat energy received per second per unit area of a perfectly black surface placed at a mean distance of the Earth form the Sun, in the absence of Earth's atmosphere, the surface being held perpendicular to the direction of Sun's rays. Its value is $1388W/m^2$. If the solar constant for the earth is 's'. The surface temperature of the sun is $TK,D$ is the diameter of the sun, $R$ is the mean distance of the Earth from the sun. The sun subtends a small angle 'theta' at the earth. Then correct options is/are:-

Supernova refer to the explosion of a massive star. The material in the central case of such a star continues to collapse under its own gravitational pull. If mass of the core is less is than $1.4$ times the mass of sun, its collapse finally results in a white dwarf star. However, if the core has a mass greater than this, it could end up soon as a neutron. star and if its mass is more than about three solar masses, the collapse may still continue till the star becomes a very small object with an extremely high value of density called a 'Black hole'. Escape speed for a black hole is very large. The figure shows a block hole of radius R and another concentric sphere of radius $R_S$, called the 'Schwarzschild Radius'. It is the critical radius at which escape speed equals the speed of light c. Nothing even the light, can escape from within the sphere of Radius $R_S$. So light from a black hole can not escape and hence the terminology 'black hole'. There has been astronomical evidence of a small and massive object at the centre of our galaxy the 'Milky way'. Suppose that there is a particle at a distance about $6$ light years. that orbits this massive object with an orbital speed of about $2\times {10}^{5}m/s$. Use the given data whereever necessary and answer the questions that hollow. $G=6.67\times {10}^{-11}N-m^2/k{g}^2$, Solar mass $M=2\times {10}^{30}kg,C=3\times {10}^{8}m/s,1$ light year $=9.5\times {10}^{15}m$.

If mass of earth $M_E\approx 6\times {10}^{24}kg$ and its radius $R_E=6400km$, to what fraction of its presents radius does the earth need to be compressed in order to become a black hole ?
(Give only the order of your answer)

In an imaginary planetary systam, the centrel star has the same mass as our sun, but is much brighter so that only a planet twice the distance between the Earth and sun can support life. According to bilogical evolution (including aging processes etc.) on that planet similar to ours, what would be the average life span of a 'human' on that planet in terms of its natural life ? The average life span of a human on the Earth may be taken to be $70$ years.