Energy Carried by Electromagnetic Waves Video Lessons

Concept

# Problem: On its highest power setting, a microwave oven can increase the temperature of 0.425 kg of spaghetti by 45°C in 120 seconds.A) What was the rate of energy absorption, in watts, by the spaghetti, given that its specific heat is 3.76 × 103 J/ (kg°C) (this is about 90% that of water)?B) Find the average intensity of the microwaves absorbed by the spaghetti, in watts per square meter, given that they are absorbed over a circular area 18.5 cm in diameter.

###### FREE Expert Solution

Power:

$\overline{)\begin{array}{rcl}{\mathbf{P}}& {\mathbf{=}}& \frac{\mathbf{Q}}{\mathbf{t}}\\ & {\mathbf{=}}& \frac{\mathbf{m}\mathbf{c}\mathbf{∆}\mathbf{T}}{\mathbf{t}}\end{array}}$

The intensity of wave:

$\overline{){\mathbf{I}}{\mathbf{=}}\frac{\mathbf{P}}{\mathbf{A}}}$

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###### Problem Details

On its highest power setting, a microwave oven can increase the temperature of 0.425 kg of spaghetti by 45°C in 120 seconds.

A) What was the rate of energy absorption, in watts, by the spaghetti, given that its specific heat is 3.76 × 103 J/ (kg°C) (this is about 90% that of water)?

B) Find the average intensity of the microwaves absorbed by the spaghetti, in watts per square meter, given that they are absorbed over a circular area 18.5 cm in diameter.