If E is the spherical excess and R the radius of the earth, the surface area of the triangle, is
πR²E/90°
πR²E/180°
πR²E/270°
πR²E/360°
Correct Answer :
B. πR²E/180°
Related Questions
The maximum error in radial line assumption, is
h/H f tan θ
h/H f² tan θ
h/H f² sin θ
h/H f cos θ
The declination and right ascension of the sun becomes 23° 27' S and 270° respectively on
March 21
June 21
September 21
December 22
Equation of time which is the difference between apparent solar time and mean solar time at any instant, vanishes during one year
Once
Twice
Thrice
Four times
The point on the photograph where bisector between the vertical line through optical centre of the camera lens and the plate perpendicular meets, is known as
Principal point
Isocenter
Plumb point
Perspective centre
At lower culmination, the pole star moves
Eastward
Westward
Northward
Southward
Polaris is usually observed for the determination of the azimuth when it is
At culmination
At elongation
Neither at culmination nor at elongation
Either at culmination or at elongation
The value of geo-centric parallax to be added to the observed altitude of sun is
9 cos α
9 sin α
9 tan α
9 cot α
The want of correspondence in stereo-photographs
Is a good property
Is a function of tilt
Is not affected by the change of flying height between photographs
Is minimum when θ is 3°
If 16 flight lines are run perpendicular to an area 30 km wide, their spacings on a photographical map on scale 1 : 50,000 , will be
1 cm
2 cm
3 cm
4 cm
The circle in which a plane tangent to the earth's surface at the point of observation, intersects the celestial sphere, is called
Visible horizon
Sensible horizon
Celestial horizon
True horizon
The point at which sun's declination changes from north to south, is known as
First point of Aeries
First point of Libra
Vernal Equinox
Both (b) and (d) of the above
H is the flying height above mean ground level and f is the principal distance of a vertical photograph. The mean scale of the photographs is
H. f
H/f
f/H
H + f
The great circle which passes through the zenith, nadir and the poles, is known as
Meridian
Vertical circle
Prime vertical
None of these
The distance between the projection centre and the photograph, is called
Principal distance
Principal line
Isocentric distance
Focal length
If the image of a triangulation station of R.L. 500 m is 4 cm from the principal point of a vertical photo taken from an altitude of 2000 m, above datum, the height displacement will be
2 mm
4 mm
6 mm
10 mm
The negative sign is assigned to
Reduction to mean sea level
Correction for horizontal alignment
Correction for slope
All the above
The scale of a vertical photograph of focal length f taken from height of H metres above M.S.L., at a point of reduced level h, is
f/H
f/(H + h)
f/(H - h)
(H - h)/f
The nautical mile is the length of
1 minute of latitude
1 minute of longitude
1 degree of latitude
1 degree of longitude
Polaris is usually observed for the determination of the latitude when it is
At culmination
At elongation
Neither at culmination nor at elongation
Either at culmination or at elongation
The difference of height of two points whose parallax difference is 0.8 mm on a pair of stereo pair taken from a height H is 100 m. If mean photo base is 95.2 mm, the flying height is
8,000 m
10,000 m
12,000 m
14,000 m
At eastern elongation, the pole star moves
Eastward
Westward
Northward
Southward
The meridian of a place is
A great circle passing through the place and the poles
A great circle whose plane is perpendicular to the axis of rotation and it also passes through the place
A semi-circle which passes through the place and is terminated at the poles
An arc of the great circle which passes through the place and is perpendicular to the equator
The product of the distances of plumb point and horizon point of a vertical photograph from its principal point, is
f2
2f2
3f2
½f
The latitude of the observer's position, is
Elevation of the elevated pole
Declination of the observer's zenith
Angular distance along the observer's meridian between equator and the observer
All the above
Pick up the incorrect statement from the following:
In truly vertical photographs without relief angles are true at the plumb point
In tilted photographs without relief, angles are true at the iso-centre
In tilled photographs with relief, angles are true at the principal point
None of these
If δ is the declination of the Polaris and λ is the latitude of the place, the azimuth of the Polaris, is
cos δ/cos λ
cos (90° - δ)/cos (90° - λ)
sin (90° - δ)/sin (90° - λ)
tan (90° + δ)/tan (90° + λ)
If α is the observed altitude, the refraction correction in seconds, is
58 cot α
58 tan α
58 sin α
58 cos α
If δ is the declination of the star and φ is the latitude of the observer then the hour angle of the star at elongation is given by
sin H = tan φ . cot δ
cos H = tan φ . cot δ
tan H = tan φ . cot δ
None of these
If two points differing by 1° of latitude and of the same longitude is 110 km apart on the earth, then two astronomical positions on the moon is about
10 km
25 km
30 km
50 km
α and β are the angles subtended by a point of elevation h at their air station with respective plumb points. Photo scale and focal length of the lens being S and f respectively. Parallax displacement of the point due to relief, is
h tan α/S
h tan β/S
h (tan α + tan β)/S
h (tan α - tan β)/S