A TV transmitting antenna is $$98 \mathrm{~m}$$ high and the receiving antenna is at the ground level. If the radius of the earth is $$6400 \mathrm{~km}$$, the surface area covered by the transmitting antenna is approximately:

An aluminium rod with Young's modulus $$Y=7.0 \times 10^{10} \mathrm{~N} / \mathrm{m}^{2}$$ undergoes elastic strain of $$0.04 \%$$. The energy per unit volume stored in the rod in SI unit is:

For the logic circuit shown, the output waveform at $$\mathrm{Y}$$ is:

The weight of a body on the earth is $$400 \mathrm{~N}$$. Then weight of the body when taken to a depth half of the radius of the earth will be: