An 8.0-mW laser beam emits a cylindrical beam of single-wavelength sinusoidal light 0.90 mm in diameter. What is the rms value of the electric field in this laser beam?
(?0 = 8.85 × 10-12 C2/N ? m2, ?0 = 4? × 10-7 T ? m/A, c = 3.0 × 108 m/s)
A) 2200 N/C
B) 1000 N/C
C) 1100 N/C
D) 4100 N/C
E) 2000 N/C
A
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Two thin layers of material with different indices of refraction are coated on a glass plate. The outer first material has n1 = 1.461, the inner second material has n2 = 1.544, and the glass has nglass = 1.62 . If light is incident from air on the first layer, what is the phase change for light that reflects from the glass?
a. 180° b. 0° c. 360° d. 540° e. 720°
A current carrying loop of wire lies flat on a table top. When viewed from above, the current moves around the loop in a counterclockwise sense
(a) For points OUTSIDE the loop, the magnetic field caused by this current A) circles the loop in a clockwise direction. B) circles the loop in a counterclockwise direction. C) points straight up. D) points straight down. E) is zero. (b) For points INSIDE the loop, the magnetic field caused by this current A) circles the loop in a clockwise direction. B) circles the loop in a counterclockwise direction. C) points straight up. D) points straight down. E) is zero.
The attractive force a 70 kg person exerts on Earth is much, much smaller than the force Earth exerts on the person.
a. true b. false
LR Circuits: A series circuit consists of an open switch, an ideal emf source ?0, a 5.0-k? resistor, and a 4.0-H inductor. If the potential across the resistor is 65.0 V at 2.0 ms after the switch is closed, find the source emf, ?0.
A. 71 V B. 36 V C. 76 V D. 56 V