$A$ non-uniformly shaped conductor is charged. Then,at its sharpest point:

One junction of a certain thermoelectric couple is at a fixed temperature $T_r$ and the other junction is at temperature $T$. The thermo-electromotive force for this is expressed by $E=k(T-T_r)[T_0-\frac{1}{2}(T+T_r)]$. At temperature $T=\frac{1}{2} T_0$,the thermoelectric power is

For the energy levels in an atom,which of the following statements is(are) correct?

The equation $\sqrt{3} \sin x + \cos x = 4$ has

The figure shows the cross-section of a long cylindrical conductor through which an axial hole of radius $r$ is drilled with its center at point $A$. $O$ is the center of the conductor. If an identical hole were to be drilled centered at point $B$ while maintaining the same current density,the magnitude of the magnetic field at $O$:

For the Bohr's first orbit of circumference $2\pi r$,the de-Broglie wavelength of the revolving electron will be