Question

Describe two energy conversions that take place when you warm a cup of cocoa in a microwave oven.

Answer 1

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here is your answer,

Describe two energy conversions that take place when you warm a cup of cocoa in a microwave oven. ... When the cocoa absorbs energy from the microwaves, electromagnetic energy is converted to thermal energy, which causes the cocoa to become warm.

Answer 2

Answer:

The two energy conversions in microwave oven are -

1. Electrical energy is converted to radiant energy (energy transmitted through electromagnetic waves/radiation).
2. Radiant energy is converted to thermal energy.

Explanation:

• Alternating current (AC) supply is given to the microwave oven to generate microwaves. Magnetrons will be present in the microwave oven which converts electrical energy into powerful microwave radiation inside the resonance cavity (space inside microwave oven).

• Microwaves are electromagnetic waves in the particular spectrum which have oscillating electric and magnetic fields.

• If we track amplitude in a specific area, we can observe the oscillation, the oscillating electric field component of the electromagnetic wave is responsible for the heat generation.

• Concept of reflection - first wave is known as incident wave and when it reaches a reflector the second wave known as reflected wave gets back towards the source point. Then one more reflector is present at the side of the source point which produces a wave same as the first wave and the process goes on.

• The resultant of the incident and reflected wave will be called as standing wave which will be maintained inside the resonance cavity.

• Most of the food particles will contain water which is a polar molecule, the hydrogen atoms are placed at an angle of 104.5° C. Both hydrogen and oxygen atoms have charges which makes the water molecule to behave like a dipole.

• When an electric field is applied on a water molecule, it starts to rotate due to the charge produced on the dipole. Since in electromagnetic waves the electric field oscillates continuously, water molecules will keep on oscillating where the molecules rub against each other producing friction and heat in the food.