Civil Engineering - Surveying - Discussion

49. 

Keeping the instrument height as 1.5 m, length of staff 4 m, the slope of the ground as 1 in 10, the sight on the down-slope, must be less than

[A]. 30 m
[B]. 25 m
[C]. 20 m
[D]. 15 m

Answer: Option B

Explanation:

No answer description available for this question.

Amar said: (Oct 3, 2013)  
staff readings visible for staff height of 2.5m so distance is 2.5x10 = 25m.

Hitesh said: (Jan 17, 2014)  
Slope = 1/10.
HI = 1.5m.

Height of staff = 4.0 m.
Sight = (4-1.5)/(1/10) = 25 m.

Mani said: (May 30, 2016)  
@Hitesh.

I'm not getting you, explain clearly.

Dilawar Memon said: (Aug 22, 2016)  
0.25 m is the answer as you discussed here.

Salma said: (Dec 11, 2016)  
I'm not getting the answer explain one again.

S.Sarkar said: (Jan 3, 2017)  
Slope 1:10 that means down 1 m for each 10 m distance.

So, 2.5 x 10 = 25 m.

G Mahesh said: (Jan 20, 2017)  
How 2.5 came?

Justin said: (Jan 23, 2017)  
Please tell me what is the different betwn downslope an upslope.

Doss said: (Jan 28, 2017)  
The instrument height of 1.5m, staff height 4m so 4 - 1.5 = 2.5m.

Ashish Tadewar said: (Mar 6, 2017)  
The Hi is 1.5m so when and staff 4m.
The reading will be 2.5m on staff on plane. The slope being 1 in 10.
2.5 * 10 = 25 on down slope.

Swami said: (Mar 10, 2017)  
Here, 2.5 * 10 = 25.

Avshesh said: (Mar 3, 2018)  
Staff visible= 4-1.5=2.5m,
Site=2.5/(1/10),
= 2.5x10,
= 25m.

Sameer Sopori said: (May 3, 2018)  
If we are levelling on the sloped surface then we need to keep staff near the instrument, otherwise, it will not be visible inside the instrument because of the slope (if the distance is more).
so here is the formula, UNDER WHICH DISTANCE WE MUST KEEP STAFF,
Sight= (Staff ht.- instrument ht.)/(1/10)
= (4 - 1.5) /0.1,
= 2.5/0.1,
= 25m.

If you will keep the staff more than 25m away from the instrument , IT WILL NOT BE VISIBLE INSIDE THE INSTRUMENT,

Mamatamayee said: (May 19, 2018)  
Thanks @Sameer.

Sagar said: (Aug 13, 2018)  
Thanks @Sameer.

Bikas said: (Feb 13, 2019)  
Thanks @sameer.

But if rising slope then maximum distance measured only 15 meters am I right?

Malla Pramod said: (Jul 14, 2019)  
Thanks all.

Shubham said: (Aug 12, 2019)  
Thanks @Sameer.

Vikash said: (Jul 6, 2020)  
Thanks all.

Waleed said: (Sep 8, 2020)  
Very helpful, Thank you @Sameer.

Ziaullah said: (Sep 10, 2020)  
4 - 1.5 = 2.5.
2.5 * 10 = 25.

Zomuana said: (Oct 25, 2020)  
Thanks a lot @Sameer.

Roohullah Jan said: (Jan 3, 2021)  
In a simple way we can say that;

Let consider the slope is downward which 1 in 10.

So at 10m, the staff reading becomes 1. 5+1=2. 5m (staff reading).

At 20 m distance reading becomes 3. 5m.

Similarly, at 25 m distance, the reading becomes 4m. Which is the full length of the staff?

Thanks.

Naveed Kamal Marwat said: (Jan 27, 2021)  
Downward 25m.

Upward 45m.

Soumya said: (Apr 27, 2021)  
If downslope 25m, If Upward slope asked then it's 55m.

Awais Khan said: (Jul 28, 2021)  
By similar triangles;
1/10 = (4-1.5)/X
X = 2.5(10) = 25m.

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