Answer:
(a) 
(b) 
Explanation:
(a) The surface current density of a conductor is the current flowing per unit length of the conductor.

Considering a wire, the current is uniformly distributed over the circumferenece of the wire.

The radius of the wire = a

The surface current density 
(b) The current density is inversely proportional
......(1)
k is the constant of proportionality

........(2)
substituting (1) into (2)





substitute 

The absorption spectrum would have all the wavelengths of the light source but would have black lines where the two red and one orange lines were in the emission spectrum
<h3><u>Answer;</u></h3>
the north end to the south end.
<h3><u>Explanation;</u></h3>
- Magnetic field lines from a bar magnet form lines that are closed. The direction of magnetic field is taken to be outward from the North pole of the magnet and in to the South pole of the magnet.
- A magnetic field refers to the area surrounding a magnet where a force is exerted on certain objects. These lines are spread out of the north end of the magnet.
- The magnetic field lines resemble a bubble.
Answer:
Acoustic microstreaming
Explanation:
Acoustic microstreaming is the swirling effect produced by water stream confined in a spaced of a periodontal pocket.
- It is the movement of water in a particular direction as a result of mechanical pressure within the fluid body.
- They are often used in dental procedures to remove particulates from the teeth.
- It mostly relies on the properties of sound waves to achieve this goal