An 800-kHz radio signal is detected at a point 9.5 km distant from a transmitter tower. The electric field amplitude of the signal at that point is 0.23 V/m
Assume that the signal power is radiated uniformly in all directions and that radio waves incident upon the ground are completely absorbed. What is the average electromagnetic energy density at that point? (c = 3.0 × 108 m/s, ?0 = 4? × 10-7 T ? m/A, ?0 = 8.85 × 10-12 C2/N ? m2 )
A) 2.3 × 10-13 J/m3
B) 9.4 × 10-13 J/m3
C) 4.7 × 10-13 J/m3
D) 3.3 × 10-13 J/m3
E) 6.6 × 10-13 J/m3
A
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An incompressible fluid is flowing through a pipe with a constriction. The pipe is on an incline with an angle of 20.0 degrees. The narrow section is 15.0 m from the wide section and the narrow section is higher than the wide section. The velocity of the fluid in the wide section of the pipe is 6.00 m/s and the velocity of the fluid in the narrow section of pipe is 9.00 m/s. The pressure of the fluid in the wide section is 250 kPa. What is the pressure in the narrow section of the pipe? (density of the fluid is 1,000
A. 217 kPa B. 205 kPa C. 180 kPa D. 177 kPa E. 157 kPa
No one can hear you scream (or fire a weapon) in space, regardless of the Hollywood special effects. Explain why
What will be an ideal response?
Which of these objects is moving with constant velocity but changing acceleration?
a. a rock dropped from a bridge b. a car going around a banked curve at 40 m/s c. an aircraft being launched off of an aircraft carrier d. an aircraft in a banked turn at 100 m/s
A charged particle (mass = M, charge = Q > 0) moves in a region of space where the magnetic field has a constant magnitude of B and a downward direction. What is the magnetic force on the particle at an instant when it is moving horizontally toward the north with a speed V?
a. QVB toward the east b. Zero c. QVB toward the west d. QVB upward e. QVB toward the south