# Practice Test: Question Set - 20

**1. A lens or combination of lenses in which the following defect is completely eliminated is called aplanatic**

- (A) Spherical
aberration

- (B) Chromatic
aberration

- (C) Coma

- (D) Astigmatism

**2. Pick up the method of surveying in which field observations and plotting proceed simultaneously from the following**

- (A) Chain
surveying

- (B) Compass
surveying

- (C) Plan
table surveying

- (D) Tacheometric
surveying

**3. For orientation of a plane table with three points**

*A*,*B*and*C*, Bessel's drill is- (A) Align

*b*through

*a*and draw a ray towards

*c*, align

*a*through

*b*and draw

*a*ray towards

*c*, finally align

*c*through the point of intersection of the previously drawn rays

- (B) Align

*c*through

*a*and draw a ray towards

*b*, align

*a*through

*c*and draw

*a*ray towards

*b*, finally align

*b*through the point of intersection of the previously drawn rays

- (C) Align

*c*through

*b*and draw a ray towards

*a*, align

*b*through

*c*and draw

*a*ray towards

*a*, finally align

*a*, through the point of intersection of the previously, drawn rays

- (D) In
the first two steps any two of the points may be used and a ray drawn towards
the third point, which is sighted through the point of intersection of
previously drawn rays in the final step.

**4. Probable accidental error in precise levelling as recommended by International Geodetic Association should not exceed (where**

*k*is in kilometers.)- (A) ± 0.1 √

*k*mm

- (B) ± 0.5 √

*k*mm

- (C) ± 1 √

*k*mm

- (D) ± 5 √

*k*mm

**5. In a telescope the object glass of focal length 14 cm, is located at 20 cm from the diaphragm. The focussing lens is midway between them when a staff 16.50 m away is focussed. The focal length of the focussing lens, is**

- (A) 5.24 cm

- (B) 6.24 cm

- (C) 7.24 cm

- (D) 8.24 cm

**6. The main principle of surveying is to work**

- (A) From
part to the whole

- (B) From whole
to the part

- (C) From higher
level to the lower level

- (D) From
lower level to higher level

**7. If Δ is the angle of deflection of the curve,**

*T*_{1}and*T*_{2}are its points of tangencies, the angle between the tangent at*T*_{1}and long chord*T*_{1}*T*_{2}will be- (A) Δ/4

- (B) Δ/3

- (C) Δ/2

- (D) Δ

**8. The rise and fall method of reduction of levels, provides a check on**

- (A) Back sights

- (B) Fore
sights

- (C) Intermediate
sights

- (D) All
of these

**9. The surface of zero elevation around the earth, which is slightly irregular and curved, is known as**

- (A) Mean
sea level

- (B) Geoid
surface

- (C) Level
surface

- (D) Horizontal
surface

**10. If the rate of gain of radial acceleration is 0.3 m per sec**

^{3}and full centrifugal ratio is developed. On the curve the ratio of the length of the transition curve of same radius on road and railway, is- (A) 2.828

- (B) 3.828

- (C) 1.828

- (D) 0.828

**11. The apparent error on reversal is**

- (A) Equal to the
actual error

- (B) Twice
the actual error

- (C) Thrice
the actual error

- (D) None
of these

**12. If the long chord and tangent length of a circular curve of radius**

*R*are equal the angle of deflection, is- (A) 30°

- (B) 60°

- (C) 90°

- (D) 120°

**13. In precision theodolite traverse if included angles are read twice and the mean reading accepted using both verniers having a least count of 30". Assuming the instrument to be in perfect adjustment, linear measurements correct to 6 mm per 30 metre tape duly corrected for temperature, slope and sag, the angular error of closure not to exceed (where**

*n*is the number of traverse legs)- (A) 50" √

*n*

- (B) 30" √

*n*

- (C) 60" √

*n*

- (D) None of these

**14. The diaphragm of a stadia theodolite is fitted with two additional**

- (A) Horizontal
hairs

- (B) Vertical
hairs

- (C) Horizontal
and two vertical hairs

- (D) None of
these

**15. Magnetic bearing of a survey line at any place**

- (A) Remains
constant

- (B) Changes
systematically

- (C) Varies
differently in different months of the year

- (D) Is
always greater than true bearing

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