Question

If observed reading of a level staff is 3.83m and at the point sighted the staff is 0.15m off the vertical
through the bottom, then correct reading will be?

Answer 1

Answer:

The difference in level b/w A and B:1.56-1.32=.24.

Apparent difference = 1.39-1.11 = .28,

True difference = 1.11 + .24 = 1.35,

Collimation error in 80m = 1.39-1.35 = 0.04.

Collimation error in 90m=(.04 * 90)÷80 = .045m.

Nd correction =.045m.

Correct staff reading on B=1.390-.045=1.345m.

Explanation:

Answer 2

Given info : If observed reading of a level staff is 3.83m and at the point sighted the staff is 0.15m off the vertical through the bottom.

To find : the correct reading will be ?

solution : a/c to question, observed reading of a level staff is 3.83 m and at the point sighted the staff is 0.15 m off the vertical through the bottom.

see figure,

observed reading of staff , 3.83 m is considered as hypotenuse of right angled triangle and height of triangle is 0.15 m (because it is off the vertical through the bottom.

now, base = √(hypotenuse ² - height ²) [ from Pythagoras theorem ]

= √(3.83² - 0.15²) = 3.827 m

Therefore the correct reading of the level staff is 3.827 m