The flood light is covered with a filter that transmits red light. The electric field of the increasing beam is represented by a sinusoidal plane wave Ex=36 sin (1.20 × 10 z-3.6 × 1015 t) V / m . The average intensity of beam in W / m 2 will be

Question

The flood light is covered with a filter that transmits red light. The electric field of the increasing beam is represented by a sinusoidal plane wave Ex=36 sin (1.20 × 10 z-3.6 × 1015 t) V / m . The average intensity of beam in W / m 2 will be (A) 6.88 (B) 3.44 (C) 1.72 (D) 0.86

Tardigrade Admin · Accepted Answer

Average intensity, I av=(1/2) ε0 E02 × C =(8.85 × 10-12 ×(36)2 × 3 × 108/2) =1.72 Wm -2

Q. The flood light is covered with a filter that transmits red light. The electric field of the increasing beam is represented by a sinusoidal plane wave $E_{x} = 36 sin (1.20 \times 10 z - 3.6 \times 1 0^{15} t) V / m .$ The average intensity of beam in $W / m^{2}$ will be

6.88

3.44

1.72

0.86

Average intensity, $I_{a v} = \frac{1}{2} ε_{0} E_{0}^{2} \times C$
$= \frac{8.85 \times 1 0 ^{- 12} \times ( 36 ) ^{2} \times 3 \times 1 0 ^{8}}{2}$
$= 1.72 W m^{- 2}$

Q. The flood light is covered with a filter that transmits red light. The electric field of the increasing beam is represented by a sinusoidal plane wave Ex​=36sin(1.20×10z−3.6×1015t)V/m. The average intensity of beam in W/m2 will be