In a spherical triangle ABC, right angled at C, sin b equals
sin a cos A
cos a sin A
tan a cot A
cot A tan a
Correct Answer :
C. tan a cot A
Related Questions
The distance between the minor control point and the principal point should be equal to
Base line of the left photograph of stereo pair
Base line of the right photograph of stereo pair
Sum of the base lines of stereo pair
Mean of the base lines of the stereo pair
The moon rotates round the earth once in every
29 days
29.35 days
29.53 days
30 days
If θ and δ be the latitude of a place and declination of a star respectively, the upper culmination of the star will be north of zenith if its zenith distance, is
δ - θ
θ - δ
θ + δ
(θ + δ)/2
In triangulation surveys
The area is divided into triangular figures
Control stations are located from which detailed surveys are carried out
Sides are not measured excepting the base line
All the above
Parallax bar measures
Parallax
Height
Parallax difference
Height difference
While making astronomical observations, the observer is mainly concerned with
The direction of the vertical, the axis of rotation of the instrument
The direction of the poles of the celestial sphere
The direction of the star from the instrument
All the above
A star in northern sphere is said to transit
When its altitude is maximum
When its azimuth is 180°
When it is in south
All the above
The solar tidal force divided by lunar tidal force is
1/3
1/2
3/4
5/4
The angle between the direction of star and the direction of earth's axis of rotation is called
Co-declination
Co-latitude
Declination
Latitude
Triangulation surveys are carried out for providing
Planimetric control
Height control
Both planimetric and height control
None of these
With standard meridian as 82° 30' E the standard time at longitude 90° E is 8 h 30 m. The local mean time at the place will be
7 h 00 m
7 h 30 m
8 h 00 m
9 h 00 m
The following points form a pair of homologous points:
Photo principal point and ground principal point
Photo isocenter and ground isocenter
Photo plumb point and ground plumb point
All the above
The Polaris remains below horizon at
10° N
50° N Latitude
Equator
5° S latitude
Pick up the correct statement from the following:
The angle between the plane of the negative and the horizontal plane containing perspective axis is the tilt of the photograph
The direction of maximum tilt is defined by the photo principal line
The principal plane is truly vertical plane which contains perspective centre as well as principal point and plumb point
All the above
If the general ground level of any area is 10% of the flying height, the principal points may be used as the centres of radial directions for small scale mapping even in tilted photograph up to
1°
2°
3°
4°
Triangulation surveys are carried out for locating
Control points for surveys of large areas
Control points for photogrammetric surveys
Engineering works, i.e. terminal points of long tunnels, bridge abutments, etc.
All 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
Spring tides are caused when
Sun and moon are in line with earth
Solar tidal force acts opposite to lunar tidal force
Solar tidal force and lunar tidal force both coincide
None of these
Circumpolar stars
Rotate round the North Pole
Rotate round the celestial pole
Remain always above the horizon
Are seldom seen near the pole star
The difference in longitude of two places expressed in time is equal to the difference in their
Sidereal time
Apparent solar time
Mean solar time
All the above
The relation between the air base (B), photographic base (b), flying height (H) and the focal length (f) of a vertical photograph, is
B = bH/f
B =f/bH
B = b/fH
B = H/bf
Pick up the correct statement for horizontal photographs.
Parallel lines do not appear parallel in central projection
The two sides of a road meet at the vanishing point
The lines parallel to the negative plane are projected as parallel lines
All the above
The shortest distance between two places measured along the surface of the earth, is
Length of the equator between their longitudes
Length of the parallel between their longitudes
Length of the arc of the great circle passing through them
None of these
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
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
The scale of a tilted photograph of focal length f, taken from an altitude H, along the plate parallel through plumb point, is
f/H sec θ
f sec θ/H
f/H
f/H cos ½θ
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
The altitude of a circumpolar star is maximum when it is
At east elongation
At upper culmination
At west elongation
At lower culmination
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 longitudes of two places at latitude 60° N are 93° E and 97° W. Their departure is
5100 nautical miles
5700 nautical miles
120 nautical miles
500 nautical miles