A tightly wound 100 turns coil of radius $$10 \mathrm{~cm}$$ carries a current of $$7 \mathrm{~A}$$. The magnitude of the magnetic field at the centre of the coil is (Take permeability of free space as $$4 \pi \times 10^{-7} \mathrm{SI}$$ units):
In an ideal transformer, the turns ratio is $$\frac{N_P}{N_S}=\frac{1}{2}$$. The ratio $$V_S: V_P$$ is equal to (the symbols carry their usual meaning) :
The graph which shows the variation of $$\left(\frac{1}{\lambda^2}\right)$$ and its kinetic energy, $$E$$ is (where $$\lambda$$ is de Broglie wavelength of a free particle):
Given below are two statements:
Statement I: Atoms are electrically neutral as they contain equal number of positive and negative charges.
Statement II: Atoms of each element are stable and emit their characteristic spectrum.
In the light of the above statements, choose the most appropriate answer from the options given below.