Aptitude - Volume and Surface Area - Discussion
Discussion Forum : Volume and Surface Area - General Questions (Q.No. 4)
4.
66 cubic centimetres of silver is drawn into a wire 1 mm in diameter. The length of the wire in metres will be:
Answer: Option
Explanation:
Let the length of the wire be h.
| Radius = | 1 | mm | = | 1 | cm. | Then, |
| 2 | 20 |
 |
22 | x | 1 | x | 1 | x h = 66. |
| 7 | 20 | 20 |
| h = |
 |
66 x 20 x 20 x 7 |  |
= 8400 cm = 84 m. |
| 22 |
Discussion:
35 comments Page 3 of 4.
Rakesh said:
1 decade ago
When 1mm diameter is converted into radius it is .5 mm or .5/1000 meter.
Prasad said:
1 decade ago
Simple. The volume is given in mm and the length in meters. Hence the length should be minimal.
Rashmi said:
1 decade ago
Can anybody say me how did we get 1/20?
Deepi said:
1 decade ago
@ Rashmi,
1cm=10milimeter
to convert mm into cm we have to multiply it by 10
1cm=10milimeter
to convert mm into cm we have to multiply it by 10
Ayush said:
1 decade ago
Please tell why the shape of wire is considered as cylinder?
Mystery said:
1 decade ago
@Ayush.
Because the wire is so small people don't tend to think of it as a cylinder but it is.
It is long and has very small radius!
Because the wire is so small people don't tend to think of it as a cylinder but it is.
It is long and has very small radius!
Hi everybody said:
1 decade ago
Actaully wire is of the form:: CYCLINDER
we know,
volume of cyclinder = π*r^2* h----------- (1)
r-radius
h-height(lenth)
Given
Diameter(d)=1mm
so r=d/2
r=(1/2)mm
r=(1/20)cm
Substitute in Eqn (1)
22/7 * (1/20)^2 *h =66 (given)
h =66 x 20 x 20 x 7/22
= 8400 cm = 84 m.
we know,
volume of cyclinder = π*r^2* h----------- (1)
r-radius
h-height(lenth)
Given
Diameter(d)=1mm
so r=d/2
r=(1/2)mm
r=(1/20)cm
Substitute in Eqn (1)
22/7 * (1/20)^2 *h =66 (given)
h =66 x 20 x 20 x 7/22
= 8400 cm = 84 m.
Amit said:
9 years ago
1/2 is divided by 10.
1/2/10 = 1/2/10 (1/2/10/1 same thing).
Then.
1/2 * 1/10 = 1/20.
1/2/10 = 1/2/10 (1/2/10/1 same thing).
Then.
1/2 * 1/10 = 1/20.
Megha said:
1 decade ago
Still I didn't get how we get 1/20? Please explain me step by step.
Uma said:
10 years ago
How we know that the wire convert into cylinder form, may be its convert other shapes.
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