Competition - post a photo you've taken of nature >>

this physics energy question has been on my mind

An electric fan heater contains an electric heater and a fan driven by an electric motor.
Describe the energy transfers that take place in the fan heater when operating normally.
Thank you for your input everyone you really helped.

(edited 7 years ago)

Reply 1

Joinedup

Original post by need urgent help

An electric fan heater contains an electric heater and a fan driven by an electric motor.
Describe the energy transfers that take place in the fan heater when operating normally.

Well can you think of anything that's getting hot or doing mechanical work in that situation?

Reply 2

mysticmagic2000

Original post by need urgent help

An electric fan heater contains an electric heater and a fan driven by an electric motor.
Describe the energy transfers that take place in the fan heater when operating normally.

Not a Physics expert LOL, but is it:

Chemical Energy -> Kinetic Energy -> Electric Energy -> heat energy?

Reply 3

LightAtTheEnd

Original post by need urgent help

An electric fan heater contains an electric heater and a fan driven by an electric motor.
Describe the energy transfers that take place in the fan heater when operating normally.

Is the fan heater connected to mains or does it have its own rechargeable battery? I will assume it is connected to mains electricity for now.

The fan is driven by an electric motor. An electric motor uses electrical energy and the use of magnets to create motion. In such a case the electrical energy is transferred to kinetic energy. The fan heater then uses this kinetic energy and transfers it to thermal/heat energy.

So the transfer should be:

Electrical energy -> Kinetic Energy -> Heat Energy + Sound energy (as heater is not 100% efficient).

If the motor uses a battery then:
Chemical Energy -> Electrical energy -> Kinetic energy -> Heat energy + Sound energy

Reply 4

mysticmagic2000

Original post by LightAtTheEnd

Hi,

Why though would electrical be before kinetic as the energy is transfering from the motor and being turned to convert into Electrical?

Reply 5

LightAtTheEnd

Original post by mysticmagic2000

Hi,

Why though would electrical be before kinetic as the energy is transferring from the motor and being turned to convert into Electrical?

The motor is the thing driving the fan yes? The electrical motor needs some input of electrical energy and using it can generate the kinetic energy that drives the fan.
It cannot move/start moving without any input of energy as that would mean energy has been created and of course this violates the first law of Thermodynamics (which states energy cannot be created nor destroyed).

If you claim that the motor uses kinetic energy and transfers it to electrical energy then your original statement would be incorrect as that is no longer an electric motor.
When we use kinetic energy to generate electric energy we call it an electric GENERATOR.

To summarise:
- If we use electrical energy to get kinetic energy (via use of magnets) then it is an electric motor.
- If we use kinetic energy to get electrical energy (via use of magnets again) then it is an electric generator.
Your question stated an electric motor so the first conversion must be happening.

Strictly speaking, an electric motor simply uses a current (hence electrical energy) and a magnetic field to create motion/movement as the interaction of the magnetic field and electric current exerts a magnetic force. As this force creates movement we can say the electrical energy is converted into the kinetic energy.

You can do additional reading on this topic by looking at Fleming's left-hand law (for motors) and right-hand law (for generators/dynamos).

(edited 7 years ago)

Reply 6

Kyx

Original post by LightAtTheEnd

Heat is not energy, it is the process by which thermal energy is transferred from one place to another. :smile:

Posted from TSR Mobile

Reply 7

LightAtTheEnd

Original post by Kyx

Heat is not energy, it is the process by which thermal energy is transferred from one place to another. :smile:

Posted from TSR Mobile

Thermal energy and heat energy mean the exact same thing. They can be used completely interchangeably. Heat is the transfer of thermal energy but heat energy and thermal energy are again the same thing.