22. Consider an infinitely long straight cylindrical conductor of radius R with its axis along the Z-direction, which carries a current of 1A uniformly distributed over its cross-section. Which of the following statements is correct?
(where, r is the radial distance from the axis of the cylinder)
(where, r is the radial distance from the axis of the cylinder)
23. A circular arc QTS is kept in an external magnetic field $${\overrightarrow {\bf{B}} _0}$$ as shown in figure. The arc carries a current $$l$$. The magnetic field is directed normal and into the page. The force acting on the arc is

24. The trace of a 3 × 3 matrix is 2. Two of its eigen values are 1 and 2. The third eigen value is
25. An infinite conducting sheet in the X-Y-plane carries a surface current density K along the Y-axis. The magnetic field $$\overrightarrow {\bf{B}} $$ for z > 0 is
26. A plane electromagnetic wave of frequency ω is incident normally on an air-dielectric interface. The dielectric is linear, isotropic, non-magnetic and its refractive index is n. The reflectance (R) and transmittance (T) from the interface are
27. A conducting sphere of radius R has charge +Q on its surface. If the charge on the sphere is doubled and its radius is halved, the energy associated with the electric field will
28. Four charges are placed at the four corners of a square of side a as shown in the figure. The electric dipole moment of this configuration is
