Each bank must report its legal reserves as well as its deposit liabilities (depositors’ funds) to the in order to show compliance with the required reserves policy ..

Federal Reserve

Explanation: The Federal Reserve is USA's central banking system. The Federal Reserve is responsible for issuing money to banks in the US, and setting the policy on monetary affairs in America. In essence every bank operates under the Federal Reserve and because of this, must report their financial status, which includes their legal reserves and deposit liabilities to the Federal Reserve. This ensures that the banks comply with the reserves policy.

The Federal Reserve

Explanation:

Also known as the Fed represents United State's Central Bank. Like every other Central Bank around the world, it is responsible for ensuring  the stability, safety and flexibility of the United State's monetary system.

Basically, there are four functions of the Federal Reserve:

1. Monitoring national monetary policies to ensure the stability of the financial system

2. Supervision of banks and protection of the right of citizens

3. Ensuring the stability of the financial market by containing any risk that may occur

4. Providing specific monetary or financial services to the government of the United States.

The need for banks to report their legal reserves and depositors' funds to the Federal Reserve is apparently a part of the supervisioning responsibility of the Federal Reserve.

sound is invisible, but sometimes we can feel it. when a kettle-drum is thumped with a stick that time the tight drum skin moving up and down very quickly for some time and then it pumped sound waves into the air. loudspeakers also work in a similar manner.

components of a speaker:

electromagnet

in order to translate an electrical signal into an audible sound, an electromagnet is used in looudspeakers

  suspension

suspension is used to   center the voice coil in the gap of the magnet and it exerts a restoring force to keep it there. suspension is used to limits the maximum mechanical excursion of the diaphragm and voice coil.

voice coil

voice coil is a coil of wire which is attached to the apex of a loudspeaker cone. it provides the motive force to the cone by the reaction of a magnetic field to the current passing through it.

cone

in a   loudspeaker, a   thin, semi-rigid membrane attached to the voice coil, which moves in a magnetic gap due to which it vibrates   and produced sound. it is known as diaphragm and it can also be called a cone, though not all speaker diaphragms are cone-shaped.

surround

surround is also known as front suspension. surround is used to join the cone to the chassis. together with the suspension it controls the cone excursion, and it is also used to   determine how energy which is   travelling through the cone is absorbed, and how the speaker limits when it reaches the ends of its travel.

dustcap

dustcap is used to protect the voice coil from dust and dirt. it is a part of the cone.

how speaker work

the outer part of the cone is fastened to the outer part of the loudspeaker's circular metal rim. the inner part is fixed to   voice coil that sits just in front of a permanent magnet . when loudspeaker is hooked up to a stereo, electrical signals feed through the speaker cables into the coil. it will convert the coil into an electromagnet magnet . when electricity flows back and forth in the cables, the electromagnet either repels or attract the permanent magnet. this moves the coil back and forth, and it pull and push the loudspeaker cone. like a drum skin vibrating back and forth, the moving cone pumps sounds out into the air.in this way loudspeakers works.

d. low interest rates