# Short-Questions

Fast solutions for complex problems

22

## Why would ferrofluid not spike?

Balance of the three forces depend on magnetization of the fluid, surface tenstion, permeability and density of the fluid. So unless the criteria given in the following eqn. is satisfied, spikes will not be formed. Ferrofluid [nano particles treated with surfactant ] exhibiting spikes due to force from magnetic field.

Why do ferrofluid form spikes?

A ferrofluid forms spikes along the magnetic field lines when the magnetic surface force exceeds the stabilizing effects of fluid weight and surface tension (see photo). The ferrofluid has low resistance to flow, so it can function as a liquid O-ring seal, kept in place with permanent magnets.

### What is ferrofluid cooling?

Ferrofluid cools down the speaker coils which are susceptible to extreme heat. Ferrofluid transfers and dissipates the thermal energy produced by the strong vibration of the moving driver. As magnets increase in temperature, they lose some of their power.

How long does ferrofluid last?

Typically ferrofluid lasts about 15 to 20 years with normal use. KEF recommends replacing ferrofluid after 15 years. If you go too long with dried up ferrofluid, the tweeter may be permanently damaged.

#### What is the point of ferrofluid?

Ferrofluids are used to form liquid seals around the spinning drive shafts in hard disks. The rotating shaft is surrounded by magnets. A small amount of ferrofluid, placed in the gap between the magnet and the shaft, will be held in place by its attraction to the magnet.

Ferrofluid is made of tiny, nanometer-sized particles of coated magnetite suspended in liquid. When there’s no magnet around, ferrofluid acts like a liquid. The magnetite particles move freely in the fluid. But when there’s a magnet nearby, the particles are temporarily magnetized.

## Is ferrofluid flammable?

Like other oils, Ferrofluid is flammable. Ferrofluid consists of billions of nano-size magnets in a liquid carrier. Ferrofluids behave as a ‘liquid magnet’ and react to external magnetic fields.

Can you touch ferrofluid?

Can you touch ferrofluid? You most certainly can but it is not recommended. Ferrofluids are considered a major skin irritant. Once you contact the ferrofluid with your finger, the liquid quickly begins to travel up the ridges of your finger and around your nail.

### Is ferrofluid poisonous?

The acute toxic reaction and the main viscera pathological morphology of mice were evaluated after oral, intravenous and intraperitoneal administration of the nano-magnetic ferrofluid of different doses respectively. So the nano-magnetic ferrofluid, of which toxicity is very low, may be used as a drug carrier.

Is it safe to touch ferrofluid?

#### What happens if you touch ferrofluid?

+ What would happen if I touched ferrofluid with my finger? You would get a dirty finger, and its very difficult to get off. Wash your hands with soap and water.

Is ferrofluid toxic?

Ingestion: This material has minimal toxicity, but fluid aspirated into lungs during ingestion could cause severe pulmonary injury or death. Do not induce vomiting; seek immediate medical attention.

## Why does a magnet attract a cold ferrofluid?

If ferrofluid is placed around the voice coil, a magnet placed near the coil will attract more cold ferrofluid than hot ferrofluid because the colder ferrofluid will be more strongly magnetized. This cold ferrofluid will absorb heat around the voice coil and then be moved towards a heat sink as it is replaced by cooler ferrofluid.

Can a ferrofluid be used as a heat sink?

This cold ferrofluid will absorb heat around the voice coil and then be moved towards a heat sink as it is replaced by cooler ferrofluid. Ferrofluids are also the focus of current scientific research and have the potential to be used in many medical applications.

### How is a ferrofluid used in a loudspeaker?

Ferrofluids can have very high thermal conductivities and their heat transfer properties are exploited in devices such as loud speakers where they are used to cool the voice coil. In a loudspeaker, sound is produced when the voice coil vibrates but this also generates unwanted heat.

How are ferrofluids used in our everyday lives?

The ferrofluid was mixed with liquid fuel and drawn towards the ignition system with an external magnetic field. Ferrofluids have now found use in many applications from small electronic devices to space crafts to cancer treatments to art. In fact, ferrofluids are found in many common household devices,…