The scale of the photography taken from a height of 300 m, with a camera of focal length 15 cm, is
1 : 10,000
1 : 15,000
1 : 20,000
1 : 30,000
Correct Answer :
C. 1 : 20,000
Related Questions
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
The point where a vertical line through the optical centre of the camera lens intersects the ground, is known as
Ground principal point
Ground plumb point
Iso-centre
Perspective centre
If S is the sum of three angles of a spherical triangle, the spherical excess equals
S - 90°
S - 180°
S - 270°
S - 360°
Pick up the in-correct statement from the following:
Apparent solar time is measured from the lower transit of the true sun
Mean solar time is measured from the lower transit of the mean sun
Sidereal time is measured from the lower transit of the first point of Aries
Sidereal time is measured from the upper transit of the first point of Aries
Parallax bar measures
Parallax
Height
Parallax difference
Height difference
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
On vertical photographs, height displacement is
Positive for points above datum
Negative for points below datum
Zero for points vertically below the air station
All the above
The station where observations are not made, but the angles at the station are used in triangulation series, is known as
Satellite station
Subsidiary station
Pivot station
Main station
The normal longitudinal overlap is generally kept
50 %
60 %
70 %
75 %
The foot of the perpendicular on the picture plane through the optical centre of the camera lens, is known as
Isocenter
Principal point
Perspective centre
Plumb line
Systematic errors
Always follow some definite mathematical law
Can be removed by applying corrections to the observed values
Are also known as cumulative errors
All the above
G.M.T. corresponding to given mean time, equals
L.M.T. - East longitude in time
L.M.T. + East longitude in time
L.M.T. - West longitude in time
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
Perspective centre relates to
Parallel projection
Orthogonal projection
Central projection
None of these
Pick up the correct statement from the following:
North end of the polar axis is known as North Pole
South end of the polar axis is known as South Pole
Point where polar axis when produced northward intersects the celestial sphere, is known as north celestial pole
All the above
The rate of change of parallax dp/dh with respect to change in h, may be expressed as
fB/(H - h)
fB/(H - h)2
fB/(H + h)
fB/(H + h)2
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
Longitude of a place is the angular distance between the meridian of the place and
The standard meridian
The international date line
That of Greenwich
Both (a) and (c) of above
The altitudes of a circumpolar star at culminations are 70° and 10°, both culminations being north of zenith. The declination of the star, is
80°
70°
60°
50°
Places having same latitude
Lie on the parallel of the latitude
Are equidistant from the nearer pole
Are equidistant from both the poles
All the above
The angular distance of a heavenly body from the equator, measured along its meridian, is called
Declination
Altitude
Zenith distance
Co-latitude
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
Pick up the incorrect statement from the following. In a spherical triangle
Every angle is less than two right angles
Sum of the three angles is equal to two right angles
Sum of the three angles less than six right angles and greater than two right angles
Sum of any two sides is greater than the third
The altitude of a heavenly body is its angular distance, measured on the vertical circle passing through the body, above
Equator
Horizon
Pole
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 First Point of Aeries
Is the point in the celestial sphere where zero meridian crosses the celestial equator
Is usually denoted by the Greek letter γ
Is located near the very conspicuous rectangle of stars in the constellations of Pegasus and Andromeda
All the above
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°
In field astronomy, the quantities observed are entirely
Lengths
Angles
Heights
All of these
The orthogonal projection of the perspective centre on a tilted photograph, is called
Nadir
Isocenter
Principal point
Plumb point
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