The student engineer of a campus radio station wishes to verify the effectiveness of the lightning rod on the antenna mast (Fig. P27.49). The unknown resistance R x is between points C and E . Point E is a true ground, but it is inaccessible for direct measurement because this stratum is several meters below the Earth’s surface. Two identical rods are driven into the ground at A and B , introducing an unknown resistance R y . The procedure is as follows. Measure resistance R 1 between points A and B , then connect A and B with a heavy conducting wire and measure resistance R 2 between points A and C . (a) Derive an equation for R x in terms of the observable resistances, R 1 , and R 2 . (b) A satisfactory ground resistance would R x < 2.00 Ω. Is the grounding of the station adequate if measurements give R 1 = 13.0 Ω and R 2 = 6.00 Ω? Explain. Figure P27.49
The student engineer of a campus radio station wishes to verify the effectiveness of the lightning rod on the antenna mast (Fig. P27.49). The unknown resistance R x is between points C and E . Point E is a true ground, but it is inaccessible for direct measurement because this stratum is several meters below the Earth’s surface. Two identical rods are driven into the ground at A and B , introducing an unknown resistance R y . The procedure is as follows. Measure resistance R 1 between points A and B , then connect A and B with a heavy conducting wire and measure resistance R 2 between points A and C . (a) Derive an equation for R x in terms of the observable resistances, R 1 , and R 2 . (b) A satisfactory ground resistance would R x < 2.00 Ω. Is the grounding of the station adequate if measurements give R 1 = 13.0 Ω and R 2 = 6.00 Ω? Explain. Figure P27.49
Solution Summary: The author explains the equation for R_x in terms of the observable resistances.
The student engineer of a campus radio station wishes to verify the effectiveness of the lightning rod on the antenna mast (Fig. P27.49). The unknown resistance Rx is between points C and E. Point E is a true ground, but it is inaccessible for direct measurement because this stratum is several meters below the Earth’s surface. Two identical rods are driven into the ground at A and B, introducing an unknown resistance Ry. The procedure is as follows. Measure resistance R1 between points A and B, then connect A and B with a heavy conducting wire and measure resistance R2 between points A and C. (a) Derive an equation for Rx in terms of the observable resistances, R1, and R2. (b) A satisfactory ground resistance would Rx < 2.00 Ω. Is the grounding of the station adequate if measurements give R1 = 13.0 Ω and R2 = 6.00 Ω? Explain.
Point charges q1 = 50 µC and q2 = −25 µC are placed 1.0 m apart. What is the magnitude of the force on a third charge q3 = 40 µC placed midway between q1 and q2? (The prefix µ =10−6 C.)
The de-excitation of a state occurs by competing emission and relaxation processes. If the relaxation mechanisms are very effective:a) the emission of radiation is largeb) the emission of radiation is smallc) the emission occurs at a shorter wavelengthd) the de-excitation occurs only by emission processes
m
C
A block of mass m slides down a ramp of height hand
collides with an identical block that is initially at rest.
The two blocks stick together and travel around a loop of
radius R without losing contact with the track. Point A is
at the top of the loop, point B is at the end of a horizon-
tal diameter, and point C is at the bottom of the loop, as
shown in the figure above. Assume that friction between
the track and blocks is negligible.
(a) The dots below represent the two connected
blocks at points A, B, and C. Draw free-body dia-
grams showing and labeling the forces (not com
ponents) exerted on the blocks at each position.
Draw the relative lengths of all vectors to reflect
the relative magnitude of the forces.
Point A
Point B
Point C
(b) For each of the following, derive an expression in
terms of m, h, R, and fundamental constants.
i. The speed of moving block at the bottom of
the ramp, just before it contacts the stationary
block
ii. The speed of the two blocks immediately…
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DC Series circuits explained - The basics working principle; Author: The Engineering Mindset;https://www.youtube.com/watch?v=VV6tZ3Aqfuc;License: Standard YouTube License, CC-BY