An 80-MW Laser Beam Emits a Cylindrical Beam of Single-Wavelength Sinusoidal

Multiple Choice

An 8.0-mW laser beam emits a cylindrical beam of single-wavelength sinusoidal light $0.90 \mathrm {~mm}$ in diameter. What is the rms value of the electric field in this laser beam? $\left( \varepsilon _ { 0 } = 8.85 \times 10 ^ { - 12 } \mathrm { C } ^ { 2 } / \mathrm { N } \right.$ . $\left. \mathrm { m } ^ { 2 } , \mu _ { 0 } = 4 \pi \times 10 ^ { - 7 } \mathrm {~T} \cdot \mathrm { m } / \mathrm { A } , c = 3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } \right)$

A) $1100 \mathrm {~N} / \mathrm { C }$
B) $2000 \mathrm {~N} / \mathrm { C }$
C) $2200 \mathrm {~N} / \mathrm { C }$
D) $1000 \mathrm {~N} / \mathrm { C }$
E) $4100 \mathrm {~N} / \mathrm { C }$