Aptitude - Volume and Surface Area - Discussion
Discussion Forum : Volume and Surface Area - General Questions (Q.No. 5)
5.
A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weighs 8 g/cm3, then the weight of the pipe is:
Answer: Option
Explanation:
External radius = 4 cm,
Internal radius = 3 cm.
| Volume of iron |
|
||||||
|
|||||||
| = 462 cm3. |
cm3
Weight of iron = (462 x 8) gm = 3696 gm = 3.696 kg.
Discussion:
60 comments Page 2 of 6.
Akanksha said:
1 decade ago
How the internal radius comes ?
Praveen Singh said:
1 decade ago
Akanksha External Radius=4 and in problem thickness=1, then Internal radius=4-1=3.thats hit...
Preeti said:
1 decade ago
Can some one explain how thickness and external radius are related. I understood we have to subtract but why?
Nats said:
1 decade ago
External radius - thickness = internal radius.
VINU said:
1 decade ago
Why subtract external radius to internal radius?
DR Sharma said:
1 decade ago
Internal radius is subtracted from the external radius to find out the volume of hollow pipe.
Venugopal said:
1 decade ago
Can you tell me the formula for Volume of iron?
Shivani said:
1 decade ago
Why there is need to multiply by 22/7?
Sahi said:
1 decade ago
@Shivani.
22/7 is the value of pi. Used in calculating volume of cylinder = pi*r^2*h.
22/7 is the value of pi. Used in calculating volume of cylinder = pi*r^2*h.
Tejas said:
1 decade ago
What is iron pipe here?
Is it volume of cylinder?
Is it volume of cylinder?
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