127. The line of sight is kept as high above ground surface as possible to minimise the error in the observed angles due to
A. shimmering
B. horizontal refraction
C. vertical refraction
D. both shimmering and horizontal refraction.

---

128. If a linear traverse follows a sharp curve round a large lake where it is difficult to have long legs, the accuracy of the traverse may be improved by
A. taking short legs
B. making repeated observations of angular and linear measurements
C. making a subsidiary traverse to determine the length of a long leg
D. all the above.

---

129. The distance between terminal points computed from a subsidiary traverse run between them, is generally known, as
A. traverse leg
B. a base
C. traverse base
D. all the above.

---

130. To avoid large centering error with very short legs, observations are generally made
A. to chain pins
B. by using optical system for centering the theodolite
C. to a target fixed on theodolite tripod on which theodolite may be fitted easily
D. all the above.

---

131. A traverse deflection angle is
A. less than 900
B. more than 90? but less than 180?
C. the difference between the included angle and 180?
D. the difference between 360? and the included angle.

---

132. In a precision traverse, included angles are measured by setting the vernier
A. to read zero exactly on back station
B. to read 5? exactly on back station
C. some where near zero and reading both verniers on back station
D. all the above.

---

133. The included angles of a theodolite traverse, are generally measured
A. clockwise from the forward station
B. anti-clockwise from the back station
C. anti-clockwise from the forward station
D. clockwise from the back station.

---