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This question contains Statement-1 and Statement-2. Of the four choices given after the statements, choose the one that best describes the two statements. Statement-1: For a mass M kept at the centre of a cube of side 'a', the flux of gravitational field passing through its sides is 4 π GM. Statement-2: If the direction of a field due to a point source is radial and its dependence on distance 'r' from the source is given as 1/r², its flux through a closed surface depends only on the strength of the source enclosed by the surface and not on the size or shape of the surface.

1. Statement-1 is false, Statement-2 is true
2. Statement-1 is true, Statement-2 is true; Statement-2 is a correct explanation for Statement-1
3. Statement-1 is true, Statement-2 is true; Statement-2 is not a correct explanation for Statement-1
4. Statement-1 is true, Statement-2 is false

Correct answer: Statement-1 is true, Statement-2 is true; Statement-2 is a correct explanation for Statement-1

Solution

By the gravitational analogue of Gauss's law, the flux through any closed surface enclosing mass M has magnitude 4*pi*G*M (independent of surface shape/size), so Statement-1 is true. Statement-2 states this very principle and is the correct explanation of Statement-1.

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