The depth of penetration of electromagnetic wave in a medium having conductivity σ at a frequency of 1 MHz is 25 cm. The depth of penetration at a frequency of 4 MHz will be

A loop antenna is a commonly used for

A. Radar

B. Direction finding

C. Satellite communication

D. All of the above

The divergence of a vector is a scalar, while the curl of a vector is another

A. Scalar

B. Vector

C. Unit vector

D. None of the above

Which antenna is a wideband antenna?

A. Hertz antenna

B. Marconi antenna

C. Folded dipole

D. None of the above

The potential that appears at a point in space due to the current which caused it is called potential

A. Accelerating

B. Retardation

C. Oscillating

D. Lagging the current