If voltage across a bulb rated $$220 \mathrm{~V}, 100 \mathrm{~W}$$ drops by $$2.5 \%$$ of its rated value, then the percentage of the rated value by which the power would decrease is

A wire of resistance $$3 \Omega$$ is stretched to twice its original length. The resistance of the new wire will be

In the given arrangement of experiment on meter bridge, if $$A D$$ corresponding to null deflection of the galvanometer is $$X$$, what would be its value if the radius of the wire $$A B$$ is doubled?

A copper wire of length $$1 \mathrm{~m}$$ and uniform cross-sectional area $$5 \times 10^{-7} \mathrm{~m}^2$$ carries a current of $$1 \mathrm{~A}$$. Assuming that, there are $$8 \times 10^{28}$$ free electrons per $$\mathrm{m}^3$$ in copper, how long will an electron take to drift from one end of the wire to the other?