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Question 1
ప్రశ్న 1
A municipal pipeline bearing was observed by compass and must be transferred to a true-north-based drawing. With east declination taken as positive and west as negative, which relationship is correct after eliminating local attraction?
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Explanation:
The magnetic bearing is referred to the magnetic meridian rather than true north. Magnetic declination is the signed angle from true north to magnetic north, taken as positive to the east. Once local attraction is removed, the true bearing equals the corrected magnetic bearing plus signed declination. The final whole-circle value is reduced modulo 360 degrees. This sign convention also handles west declination by giving it a negative value. Local attraction must not be mistaken for the regional declination correction.
వివరణ:
Question 2
ప్రశ్న 2
At a station verified free of local attraction, a line has magnetic whole-circle bearing 074°20′. Magnetic declination is 3°40′ EAST. What is its TRUE whole-circle bearing?
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Explanation:
An easterly declination is positive in the stated bearing convention. The true bearing equals the corrected magnetic bearing plus the easterly declination. Adding 074°20′ and 3°40′ gives 078°00′. No extra station correction is necessary because the station is verified unaffected. The result is already within the whole-circle range. Subtracting the declination would reverse the east-west sign convention.
వివరణ:
Question 3
ప్రశ్న 3
An independently established TRUE bearing is 012°30′. At the survey site magnetic declination is 5°15′ WEST, and local attraction is absent. What MAGNETIC whole-circle bearing should the compass indicate?
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Explanation:
A west declination is a negative signed quantity. The relation is true bearing equals magnetic bearing plus signed declination. Therefore the magnetic bearing equals 012°30′ minus negative 5°15′. The result is 017°45′. No wraparound adjustment is required. The given true bearing should not be confused with the opposite-direction back bearing.
వివరణ:
Question 4
ప్రశ్న 4
A compass line, observed at a station free from local attraction, has magnetic bearing 357°40′. East declination is 4°50′. What is its normalized TRUE whole-circle bearing?
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Explanation:
The easterly declination must be added to the magnetic bearing. The unnormalized sum is 357°40′ + 4°50′ = 362°30′. A whole-circle bearing must lie between zero inclusive and 360 degrees exclusive. Subtracting 360 degrees yields 002°30′. The line therefore lies slightly east of true north. Reporting 362°30′ without normalization is not the conventional final bearing.
వివరణ:
Question 5
ప్రశ్న 5
For the same undisturbed line, the true whole-circle bearing is 205°10′ while the corrected magnetic bearing is 211°40′. What magnetic declination follows from the signed-bearing relationship?
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Explanation:
Declination is determined as true bearing minus corrected magnetic bearing. Subtracting 211°40′ from 205°10′ gives negative 6°30′. A negative declination denotes a westward magnetic meridian under the stated convention. Hence the declination is 6°30′ west. This difference is not evidence of local attraction because both bearings are stated to be referred to undisturbed meridians. The opposite east sign would give an incorrect true bearing on substitution.
వివరణ:
Question 6
ప్రశ్న 6
At an observatory the declination changed from 2°40′ EAST to 1°10′ EAST over exactly five years. Assume a uniform secular change for this exercise. What was the average annual change in signed declination?
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Explanation:
The easterly declination decreased from 160 minutes to 70 minutes of arc. Its total signed change is negative 90 minutes over five years. Dividing by five gives negative 18 minutes of arc per year. The negative result describes a westward change of the declination value. It does not imply that the declination itself became west during the period. The specified uniform-rate assumption permits the simple average calculation.
వివరణ:
Question 7
ప్రశ్న 7
A compass station is checked on several occasions. The needle direction changes slowly over years, fluctuates during a day, and shows an exceptional short-lived disturbance during a magnetic storm. Which interpretation best distinguishes these observations?
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Explanation:
Earth's magnetic field changes at different time scales. A long-term change in declination is commonly described as secular variation. Changes within the daily cycle are diurnal variations. Geomagnetic disturbances may also cause irregular short-term changes. These temporal effects should be distinguished from station-specific magnetic interference caused by nearby objects. High-accuracy compass work may require observations or corrections appropriate to the observation date and conditions.
వివరణ:
Question 8
ప్రశ్న 8
Two nearby compass stations share essentially the same regional magnetic declination, but one is beside an energized power cable and the other is in a cleared area. Which statement is technically most defensible?
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Explanation:
Magnetic declination is the angular difference between magnetic and true north at a place and time. It is distinct from a station-specific disturbance of the magnetic needle. An energized cable may create a local magnetic field that affects a nearby compass. The other station can remain comparatively unaffected by the cable. Converting a disturbed observation to true north requires both an appropriate local-attraction correction and declination. Applying declination alone cannot remove the cable-induced station error.
వివరణ:
Question 9
ప్రశ్న 9
For line AB, a compass gives observed fore bearing 062° and observed back bearing 244°. Treat meridian convergence as negligible and assume consistent observation conditions. Which conclusion is justified by these readings ALONE?
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Explanation:
The expected reverse bearing corresponding to 062° is 242°. The observed reverse bearing is 244°, giving a two-degree discrepancy. A disturbed meridian at either endpoint can create such a difference. Measurement or reading error can produce a discrepancy as well. The readings alone do not establish the individual station biases. Independent control or further lines are needed before assigning a station correction.
వివరణ:
Question 10
ప్రశ్న 10
A known line has independently verified undisturbed magnetic bearing 135°00′. At station P the compass observes that line as 138°30′. Assume a uniform additive local-attraction bias for ALL directions observed at P during this setup. What correction must be APPLIED to P's observed whole-circle bearings?
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Explanation:
The compass observation exceeds the known correct magnetic bearing by 3°30′. Thus the additive observation bias at P is positive 3°30′. A correction must have the opposite sign to the bias. Every bearing observed under the same station setup receives −3°30′ before normalization. This is a station correction and not a change in regional magnetic declination. The known reference direction supplies the independent information needed to establish its value.
వివరణ:
Question 11
ప్రశ్న 11
In a short open traverse A–B–C–D, stations A and B are independently verified free of local attraction. The observed magnetic bearings are AB = 068°, BA = 248°, BC = 132°, CB = 310°, and CD at C = 205°. Assume negligible measurement error and a constant additive bias at each affected station. What is the CORRECTED magnetic bearing of CD?
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Explanation:
BC is observed from unaffected station B and therefore has correct magnetic bearing 132°. Its correct back bearing at C must be 312°. The observed CB is only 310°, indicating a negative 2° station bias at C. The correction to every bearing observed at C is consequently +2°. Applying it to observed CD = 205° gives 207°. The undisturbed AB/BA pair supplies a consistency check for the stated reference stations.
వివరణ:
Question 12
ప్రశ్న 12
In open traverse A–B–C–D–E, stations A and B are independently verified free of local attraction. Observations are BC from B = 120°, CB from C = 298°; CD from C = 192°, DC from D = 016°; and DE from D = 285°. Treat each station bias as constant and ignore observational error. What is the CORRECTED magnetic fore bearing of DE?
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Explanation:
BC is correct at 120° because it was observed from unaffected B. Its correct reverse at C is 300°, while observed CB is 298°. The correction at C is therefore +2°, making corrected CD equal to 194°. The correct reverse of corrected CD is 014° at D. Since observed DC at D is 016°, station D has a positive 2° bias and requires a −2° correction. Corrected DE is accordingly 285° − 2° = 283°.
వివరణ:
Question 13
ప్రశ్న 13
In open traverse P–Q–R–S, stations P and Q are independently verified unaffected by local attraction. Observed bearings are QR at Q = 143°20′, RQ at R = 325°05′, RS at R = 217°10′, and SR at S = 034°55′. Assume a constant additive local bias at each station and negligible reading errors. What correction must be applied to ALL bearings observed at S?
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Explanation:
The undisturbed bearing QR is 143°20′. The correct reverse RQ must be 323°20′. Since R observes 325°05′, R has a positive bias of 1°45′ and requires a correction of −1°45′. Corrected RS is therefore 217°10′ − 1°45′ = 215°25′. Its correct reverse SR is 035°25′, whereas S observes 034°55′. S has a negative bias of 0°30′ and needs a positive correction of 0°30′.
వివరణ:
Question 14
ప్రశ్న 14
A station A is independently verified unaffected by local attraction. On AB its observed forward magnetic bearing is 047°00′, while station B observes the reverse BA as 229°30′. B also observes BC as 112°15′. Assuming one constant additive bias at B, what is the CORRECTED magnetic bearing of BC?
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Explanation:
AB from unaffected A is correct at 047°00′. The correct reverse direction BA must be 227°00′. Station B observes BA as 229°30′, which is 2°30′ too high. All bearings observed at B therefore require a correction of −2°30′. Correcting BC from 112°15′ gives 109°45′. No true-meridian declination correction is needed because the question asks for the undisturbed magnetic bearing.
వివరణ:
Question 15
ప్రశ్న 15
In open traverse A–B–C–D, station D is independently verified unaffected by local attraction. The observations are CD at C = 201°, DC at D = 017°, BC at B = 121°, CB at C = 303°, and BA at B = 251°. Assume a uniform additive station bias and negligible other errors. What is the CORRECTED magnetic bearing AB?
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Explanation:
The correct reverse of observed DC = 017° at unaffected D is CD = 197°. Therefore the observed CD = 201° has a +4° bias at C and requires −4° correction. Corrected CB is 303° − 4° = 299°, making the correct BC direction 119°. B observed BC as 121°, so B requires a −2° correction. Corrected BA is 251° − 2° = 249°. The correct forward bearing AB is the reverse direction, 069°.
వివరణ:
Question 16
ప్రశ్న 16
At a compass station affected by a fixed additive local magnetic bias, two rays have observed whole-circle bearings 054° and 126°. Both were observed without changing the setup or bias. What is the SMALLER included angle between these rays?
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Explanation:
Both observed directions at the station contain the same additive local-attraction bias. Subtracting one bearing from the other cancels that common bias. The angular difference is 126° − 54° = 72°. This value is already smaller than 180 degrees and is therefore the smaller included angle. A correction is needed to express either ray as an undisturbed magnetic bearing, but not to obtain their angle from a common affected setup. Observations taken at different stations would not generally enjoy this same cancellation.
వివరణ:
Question 17
ప్రశ్న 17
A particular line has fixed TRUE bearing 140°. At the same site, east magnetic declination decreases from 3° to 1° between two surveys, and both compass setups are free from local attraction. How does the MAGNETIC bearing of that fixed line change?
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Explanation:
The true bearing of a fixed physical line remains 140° in this idealized comparison. Magnetic bearing equals true bearing minus signed declination. With 3° east declination, magnetic bearing is 140° − 3° = 137°. With 1° east declination, it becomes 140° − 1° = 139°. The magnetic bearing therefore increases by two degrees. This is a change in the magnetic reference direction, not a physical rotation of the line.
వివరణ:
Question 18
ప్రశ్న 18
The observed fore and back bearings of AB are 050° and 230°, exactly 180° apart. No independent meridian reference or other traverse observations are available. Which inference is strictly justified?
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Explanation:
The observed reversal satisfies the expected 180-degree relation. That agreement is a useful routine check. However, equal additive magnetic biases at A and B would also preserve the 180-degree difference. The two readings alone cannot distinguish equal biases from zero bias. Independent undisturbed control, additional network observations or magnetic checks are required for certainty. Routine examination practice may presume an exactly reversing line is undisturbed, but that is an assumption rather than a strict logical proof.
వివరణ:
Question 19
ప్రశ్న 19
For a short line AB, observed fore bearing at A is 073°00′ and observed back bearing at B is 254°30′. An independent check establishes that the additive magnetic bearing bias at A is +1°00′. Neglect meridian convergence and observation errors. What is the additive BIAS at B?
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Explanation:
Correcting the observed forward bearing at A requires subtracting its known +1°00′ bias. The undisturbed AB bearing is 072°00′. Its correct back bearing BA at B is 252°00′. The observed BA is 254°30′, higher by 2°30′. Thus B has a positive additive bearing bias of 2°30′. To correct readings at B, the surveyor would apply −2°30′ rather than +2°30′.
వివరణ:
Question 20
ప్రశ్న 20
At a station with an unchanged additive compass bias, two lines have observed bearings 350° and 035°, measured clockwise from the same magnetic reference. What is their SMALLER included angle?
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Explanation:
The bearings straddle the zero-degree direction. Their ordinary numerical difference is 350° − 35° = 315°. The smaller included angle is the remaining portion of the full circle, 360° − 315° = 45°. A common additive station bias shifts both bearings by the same amount. It therefore does not alter the included angle. The result also shows why angular differences must be normalized around 360 degrees.
వివరణ:
Question 21
ప్రశ్న 21
A traverse has observed fore bearing AB = 061° at A, observed back bearing BA = 243° at B, and observed fore bearing BC = 134° at the SAME setup at B. Assume any local attraction at B is a constant additive bearing bias. What is the SMALLER included angle ABC as determined directly from the two observations at B?
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Explanation:
The included angle at B is formed by rays BA and BC. Both of their directions were observed from the same station under an unchanged setup. Their common station bias cancels when their bearings are differenced. The difference between 243° and 134° is 109°. This is the smaller included angle because it is below 180 degrees. The fore bearing at A need not be corrected to determine this local included angle.
వివరణ:
Question 22
ప్రశ్న 22
In open traverse A–B–C–D, station B is independently verified free of local attraction. BC observed at B is 350°, CB observed at C is 172°, and CD observed at C is 085°. Assume station-specific additive bias, negligible reading error, and magnetic declination 4° EAST throughout. What is the TRUE bearing of CD?
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Explanation:
The undisturbed magnetic bearing BC is 350° because B is unaffected. The correct back bearing CB at C is 170°. Observed CB is 172°, indicating a +2° local bias at C. Corrected magnetic bearing CD is therefore 085° − 2° = 083°. East declination of 4° must then be added to the corrected magnetic bearing. Hence the true whole-circle bearing of CD is 087°.
వివరణ:
Question 23
ప్రశ్న 23
A surveyor knows from independent geodetic control that the TRUE bearing of a reference line from station S is 125°. Local east declination is 3°, but the compass at S observes that reference line as 125°. All observations at S share the same additive local attraction bias. A second line from S is observed as 278°. What is the TRUE bearing of that second line?
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Explanation:
The correct magnetic bearing of the reference line is true bearing minus east declination, or 125° − 3° = 122°. Its observed bearing of 125° is therefore 3° too high due to the station bias. The second observed bearing must first be reduced by 3°, giving corrected magnetic bearing 275°. Adding 3° east declination converts that second line to true bearing 278°. Both corrections are necessary, even though their numerical effects cancel in this example. The independent true-bearing reference enables the local bias to be determined.
వివరణ:
Question 24
ప్రశ్న 24
During a magnetic compass survey beside a steel pipe rack, a station gives inconsistent magnetic bearings when compared with independently established control. Which field response is most appropriate?
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Explanation:
Local magnetic attraction can be caused by nearby steel masses or electrical currents. Such disturbances may prevent a compass needle from aligning with the expected magnetic meridian. The immediate priority is to identify and reduce the local interference where practicable. Bearings should be checked against independent control or observations from unaffected stations. Moving the instrument or adopting an appropriately controlled nonmagnetic method may be necessary. Regional declination correction alone does not eliminate station-specific magnetic disturbance.
వివరణ:
Question 25
ప్రశ్న 25
In open traverse A–B–C–D–E–F, stations A and B are independently verified unaffected by local attraction. Observed magnetic bearings are BC at B = 112°40′, CB at C = 291°10′, CD at C = 214°15′, DC at D = 036°30′, DE at D = 296°10′, ED at E = 115°00′, and EF at E = 062°15′. Assume a constant additive bias at each station, negligible observational error, and declination 2°20′ WEST. What is the TRUE bearing of EF?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
BC observed at unaffected B is 112°40′, so the correct CB is 292°40′ and C requires +1°30′ correction. Therefore corrected CD is 215°45′ and its reverse DC should be 035°45′. Observed DC is 036°30′, so station D requires −0°45′ correction. Corrected DE is 295°25′, whose reverse ED is 115°25′, making E require +0°25′ correction. Corrected magnetic EF is 062°15′ + 0°25′ = 062°40′. Adding signed west declination −2°20′ gives true bearing 060°20′.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: B. True bearing = corrected magnetic bearing + signed declination, normalized to 0°–360°. సమాధానం: B.
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Question 2 ప్రశ్న 2Answer: D. 078°00′. సమాధానం: D.
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Question 3 ప్రశ్న 3Answer: A. 017°45′. సమాధానం: A.
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Question 4 ప్రశ్న 4Answer: C. 002°30′. సమాధానం: C.
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Question 5 ప్రశ్న 5Answer: B. 6°30′ WEST. సమాధానం: B.
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Question 6 ప్రశ్న 6Answer: D. 18′ per year towards the west. సమాధానం: D.
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Question 7 ప్రశ్న 7Answer: C. Long-term secular variation, diurnal variation, and irregular disturbance are different temporal components of geomagnetic change. సమాధానం: C.
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Question 8 ప్రశ్న 8Answer: A. Regional declination changes the reference from magnetic to true north; the cable can create additional local attraction at its nearby station. సమాధానం: A.
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Question 9 ప్రశ్న 9Answer: B. The fore/back departure from the ideal 180° is 2°; local attraction or observation error is indicated, but the affected station cannot be uniquely identified. సమాధానం: B.
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Question 10 ప్రశ్న 10Answer: D. −3°30′. సమాధానం: D.
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Question 11 ప్రశ్న 11Answer: C. 207°. సమాధానం: C.
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Question 12 ప్రశ్న 12Answer: A. 283°. సమాధానం: A.
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Question 13 ప్రశ్న 13Answer: B. +0°30′. సమాధానం: B.
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Question 14 ప్రశ్న 14Answer: D. 109°45′. సమాధానం: D.
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Question 15 ప్రశ్న 15Answer: C. 069°. సమాధానం: C.
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Question 16 ప్రశ్న 16Answer: A. 72°. సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: B. It increases from 137° to 139°. సమాధానం: B.
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Question 18 ప్రశ్న 18Answer: D. The observations are consistent with equal additive station biases; they do not ALONE prove that both stations are free from local attraction. సమాధానం: D.
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Question 19 ప్రశ్న 19Answer: C. +2°30′. సమాధానం: C.
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Question 20 ప్రశ్న 20Answer: A. 45°. సమాధానం: A.
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Question 21 ప్రశ్న 21Answer: B. 109°. సమాధానం: B.
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Question 22 ప్రశ్న 22Answer: D. 087°. సమాధానం: D.
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Question 23 ప్రశ్న 23Answer: C. 278°. సమాధానం: C.
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Question 24 ప్రశ్న 24Answer: A. Investigate nearby ferrous objects and electrical sources, check the compass against independent control, and reoccupy a suitable undisturbed station or use a nonmagnetic reference method when necessary. సమాధానం: A.
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Question 25 ప్రశ్న 25Answer: B. 060°20′. సమాధానం: B.