Question

PLEASE LET ME KNOW THE KNSWER QUICKLY AND CORRECTLY. IF YOU SPAM I AM GOING TO REPORT. PLEASE DONT SPAM→∅

(i) Take a cylindrical can or box and trace the base of the can on graph paper and cut

it [Fig 11.39(i)]. Take another graph paper in such a way that its width is equal to

the height of the can. Wrap the strip around the can such that it just fits around the

can (remove the excess paper) [Fig 11.39(ii)].

Tape the pieces [Fig 11.39(iii)] together to form a cylinder [Fig 11.39(iv)]. What is

the shape of the paper that goes around the can?

Of course it is rectangular in shape. When you tape the parts of this cylinder together,

the length of the rectangular strip is equal to the circumference of the circle. Record

the radius (r) of the circular base, length (l) and width (h) of the rectangular strip.

Is 2πr = length of the strip. Check if the area of rectangular strip is 2πrh. Count

how many square units of the squared paper are used to form the cylinder.

Check if this count is approximately equal to 2πr (r + h).

(ii) We can deduce the relation 2πr (r + h) as the surface area of a cylinder in another

way. Imagine cutting up a cylinder as shown below (Fig 11.40).

NOTE:

The lateral (or curved) surface area of a cylinder is 2πrh.

The total surface area of a cylinder = πr2

+ 2πrh + πr2

= 2πr2

+ 2πrh or 2πr (r + h)

FOR IMAGE:
http://www.ncert.nic.in/ncerts/l/hemh111.pdf
PAGE NO. : 15 AND 16

Answer 1

Answer:

First of all, answer of your question depends on how big cylinder you take

But I still don't understand what the question is

I mean you just copy pasted an activity