Question

A microwave has a width of 29 inches, depth of 15 inches, and a height of 16 inches. The power of the microwave is 1.65 kW. Use this information to solve these questions. Assume that microwave energy is generated uniformly on the upper surface of the cavity and propagates directly downward toward the base. The base is lined with a material that completely absorbs microwave energy. (c = 3.00 × 108 m/s, μ0 = 4π × 10-7 T ∙ m/A, ε0 = 8.85 × 10-12 C2/N ∙ m2) 1. What is the intensity of the microwave beam? 2. What is the amplitude of the electric field? 3. What is the total microwave energy content of the cavity? (hint first find energy density) 4. What is the magnitude of force does the microwave beam exert on the base of the oven?

Answer 1

Part 1)

The intensity of the microwave beam is defined as the average power per unit area transported by the beam

Area,

  

So,  

Part 2)

Intensity can also be written in terms of electric field amplitude

Part 3)

Energy density is given as

The total microwave energy content is given as

Part 4)

The average force per unit area is given as