Question

The rate of energy flow per unit area of electromagnetic wave has an average value of 0.695 W/m2. The wave is incident at right angles upon a rectangular area measuring 1.5 m by 2.0 m. How much total energy falls upon this rectangle each minute? (\small \epsilon0=8.85 x 10-12 C2/Nxm2, u0=4\small \prodx10-7 Txm/A, c=?3.0 x 108 m/s)

Answer 1

Answer:

125.1 Joules

Explanation:

P = Power

t = Time

A = Area

Intensity is given by

$I=\frac{P}{A}$

Energy is given by

$E=Pt\\\Rightarrow P=\frac{E}{t}$

For one second

$\frac{E}{t}=IA\\\Rightarrow E=IAt\\\Rightarrow E=0.695\times 1.5\times 2\times 1\\\Rightarrow E=2.085\ J$

The energy falling on the rectangle is 2.085 Joules every second

In one minute

$2.085\times 60=125.1\ J$

In one minute the energy falling on the rectangle is 125.1 Joules