Civil Engineering - Surveying - Discussion

Discussion Forum : Surveying - Section 4 (Q.No. 5)
5.
Which of the following introduces an error of about 1 in 1000 if 20 m chain is used
length of chain 20 mm wrong
one end of the chain 0.9 m off the line
one end of chain 0.9 m higher than the other
middle of the chain 0.45 m off the line
all the above.
Explanation:
No answer description is available. Let's discuss.
Discussion:
12 comments Page 1 of 2.

Shah Sawar said:   3 years ago
Slope Correction or error = h^2/2L.

Now we want to find the difference in height of chain ends for which 1 in 1000 or 20 mm in 20 m chain length will produce.

0.02 = h^2/(2 x 20),
h = 0.9 m,
So, option B along with A, C options is correct.
(2)

Sudip said:   4 years ago
Slope error= 20mm = h^2/2L.
Then, h=0.89m~0.9m.
i.e. one end is 0.9m higher/lower than another end.
(1)

Ravikiran s said:   8 years ago
So which one is clear I mean which gives accurate reading without an error.

Saikat said:   6 years ago
1 in 1000 means 1000 m = 1m.
then 20 m = 1/1000* 20=20mm.

Maithri said:   4 years ago
Can you explain how you got 0.89 @Sudip.

Ritu said:   6 years ago

Laxmi said:   4 years ago

NAMAN soni said:   4 years ago