Answer:
Option D is correct: 170 µW/m²
Explanation:
Given that,
Frequency f = 800kHz
Distance d = 2.7km = 2700m
Electric field Eo = 0.36V/m
Intensity of radio signal
The intensity of radial signal is given as
I = c•εo•Eo²/2
Where c is speed of light
c = 3×10^8m/s
εo = 8.85 × 10^-12 C²/Nm²
I = 3×10^8 × 8.85×10^-12 × 0.36²/2
I = 1.72 × 10^-4W/m²
I = 172 × 10^-6 W/m²
I = 172 µW/m²
Then, the intensity of the radio wave at that point is approximately 170 µW/m²
Answer:
B. It changes the objects direction
Answer:
Explanation:
consider the principle of moment
when a system is in equilibrium, the clockwise moment (torque) about the pivot is equal to the counterclockwise moment ( torque). Since the plank is uniform the weight of the plank act at the middle which = 6.1 m / 2 = 3.05 m
the distance that can support the weight of the man = d
mass of the man = 70
70 × d = 33 × ( 3.05 - 1.6)
d = 47.85 / 60 = 0.798 m, if the man work beyond this point he will fall.
Answer:
A) having each person listen to just 1 song instead of 5.
Explanation:
Ravi could accurately use the outcome to compare the hearing capacities of his friends by this experiment if appropriate precautions are observed.
Playing 5 well known songs simultaneously could result to the interference of sounds when each participant moves away from the player. Which could naturally cause the variation in volume of the songs played with respect to the increasing distance.
Therefore, the reliability of the result from this experiment can be increased if each person listen to just 1 song instead of 5 at a predetermined volume. Each participant would be able to focus on hearing a song during the experiment.