The negation of the statement, "The payment will be made if and only if the work is finished in time" is

The magnetic susceptibility of the material of a rod is 349 and permeability of vacuum $$\mu_0$$ is $$4 \pi \times 10^{-7}$$ SI units. Absolute permeability of the material of the rod in SI units is

The magnetic flux through a coil of resistance '$$R$$' changes by an amount '$$\Delta \phi$$' in time '$$\Delta \mathrm{t}$$'. The total quantity of induced electric charge '$$\mathrm{Q}$$' is

A body weighs $$500 \mathrm{~N}$$ on the surface of the earth. At what distance below the surface of the earth it weighs $$250 \mathrm{~N}$$ ? (Radius of earth, $$\mathrm{R}=6400 \mathrm{~km}$$ )