# Civil Engineering - UPSC Civil Service Exam Questions - Discussion

Discussion Forum : UPSC Civil Service Exam Questions - Section 22 (Q.No. 7)
7.
If a 30 m length can be taped with a precision of ± 0.01 m, then the standard error of measuring 1.08 km with the same precision will be
± 0.54 m
± 0.45 m
± 0.36 m
± 0.06 m
Explanation:
No answer description is available. Let's discuss.
Discussion:
13 comments Page 1 of 2.

RAHUL said:   1 year ago
CORRECTED LENGTH = 1080 * (30+-.01)/30.
1080+-.36.
ERROR = MEASURED VALUE - TRUE VALUE.
=(1080+-36)-1080,
=±0.36.
(1)

Apcivilian said:   2 years ago
I think C) 0.36 is the right answer.
(1)

Er. Satyam vishwakarma said:   2 years ago
Std error = +- &radic of no. Of measurement.
Std error = +- 6*e.
= +- 0.06m.

Raunak said:   3 years ago
Total error = +-(N x (error in the chain)^2).
N = no.of chain (L/30).

Soumyajit Mandal said:   4 years ago
The law of probability states that error(e) is proportional to sqrt of that line(L).

Therefore,
e1/e2 = √L1/√L2.
=>0.01/e2 = √30/√1080.
=>e2 = 0.06.
(2)

Kalpana said:   5 years ago

Binay yadav said:   5 years ago

Arjun said:   5 years ago
Here, e is directly proportional to the √l.

Dhaval said:   5 years ago
I think C is the right answer.

Phani said:   6 years ago
Ans = 1.08 * 1000 * 0.01 ÷ 30,
= 0.36.