If f is the focal length of the camera lens and θ is the angle of tilt, the distance of the plumb point from the principal point will be
f sin θ
f cos θ
f tan θ
f sec θ
Correct Answer :
C. f tan θ
Related Questions
Pick up the correct statement from the following:
The vertical plane containing the zenith, the station of observation and the celestial pole is the observer's meridian plane
The angle between the direction of star in vertical plane and the direction of the star in horizontal plane is called the altitude of the star
The complement of the altitude of star is called the zenith distance of the star
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°
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
In observations of equal precision, the most probable values of the observed quantities are those that render the sum of the squares of the residual errors a minimum, is the fundamental principle of
Gauss' Mid Latitude formula
D'Alembert's method
Legendre's method
Least square method
Pick up the incorrect statement from the following. The angular distance of heavenly bodies on observer's meridian measured from the pole, is
Co-declination
Co-altitude
Co-latitude
Polar distance
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 difference of parallax for a given difference in elevation is independent of
Focal length of the camera
Overall size of the photo graphs
Percentage of overlap
All the above
The hour angle of the heavenly body for Greenwich meridian equals the hour angle of the body for any other meridian + longitude:
Mean sun
True sun
Vernal equinox
All the above
At western elongation, the pole star moves
Eastward
Westward
Northward
Southward
According to Napier's Rules of circular parts for a right angled triangle, sine of middle part equals the product of
Tangents of two adjacent parts
Sines of two adjacent parts
Cosines of two adjacent parts
Both (a) and (b) above
To have greatest coverage of the area, the type of photography used, is
High oblique
Low oblique
Vertical
None of these
The altitude of a circumpolar star is maximum when it is
At east elongation
At upper culmination
At west elongation
At lower culmination
If α, H, A and δ be the altitude, hour angle, azimuth and declination of a circumpolar star at its elongation, in latitude λ, the following relation holds good
cos H = tan λ/tan δ
sin α = sin λ/sin δ
sin A = cos δ/cos λ
All the above
The correction for parallax, is
- 8.8 cos α
+ .8 sin α
+ 8.8 cos α
- 8.8 cos α
The coverage is least if photography is
High oblique
Low oblique
Vertical
None of these
Pick up the in-correct statement from the following:
Correction for refraction is always negative
Correction for parallax is always positive
Correction for semi-diameter is always negative
Correction for dip is always negative
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
For adjusting a quadrilateral whose both the diagonals are observed, the equations of conditions involved, are
Two angle equations and two side equations
One angle equation and three side equations
Three angle equations and one side equation
None of these
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
If δ is the declination of the star and φ is the latitude of the observer, then the azimuth of the star at elongation is given by
sin z = sec φ . cos δ
cos z = sec φ . cos δ
tan z = sec φ . cos δ
None of these
The point where vertical line passing through the perspective centre intersects the plane of the photograph, is known as
Photo plumb point
Plumb point
Nadir point
Isocenter
The time interval between successive transits of the moon, is
24 hours 10 minutes
20 hours 25 minutes
24 hours 50 minutes
23 hours 50 minutes
The great circle along which the sun appears to trace on the celestial sphere with earth as centre during the year, is called
Equator
Celestial equator
Ecliptic
None of these
Pick up the correct statement from the following:
The star's movement is apparent due to the actual steady rotation of the earth about its axis
The stars move round in circular concentrated parts
The centre of the circular paths of stars is the celestial pole
All the above
Homologous points are
Opposite corners of a photograph
Nodal points of the camera lens
Corresponding points on the ground and photograph
Plumb points of stereo pair of photographs
Longitudes are measured from 0° to
180° eastward
180° westward
180° east or westward
360° eastward
A plate parallel is the line on the plane of the negative
Parallel to the principal line
Perpendicular to the principal line
Along the bisector of the angle between the principal line and a perpendicular line through principal plane
None of these
In field astronomy, the quantities observed are entirely
Lengths
Angles
Heights
All of these
The Polaris describes a small circle round the pole whose radius is approximately
1°
2°
3°
4°
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