Question & Answer: Page 1

Anurag asks : If the diameter of the base of a closed right circular cylinder be equal to its height h,then its whole surface area is? (a) 2*pie*h square (b) 3/2*pie*h square (c) 4/3*pie*h square (d) pie*h square

Tag : diameter,height,cylinder,closed,surface,square,pieh,equal,cbse,hthen,circular

Category : CBSE | On : 2012-03-05 12:52:22

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Harminder singh says :

05/03/2012 08:31:47

answer is none of these as it is pie*(h/2) sqr + pie*h*h/2= 3/4 pie* h sqr

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Anurag asks : In a circle of radius 17cm,two parallel chords are drawn on opposite side of a diameter.The distance between the chords is 23cm.If the length of one chord is 16cm,then the length of the other is:- (a) 34 cm (b) 15 cm (c) 23 cm (d) 30 cm

Tag : cbse,length,drawn,chords,radius,opposite,side,parallel,distance,diameter,circle

Category : CBSE | On : 2012-03-04 12:51:24

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Vinnie says :

04/03/2012 01:43:23

length of other is also 30cm. in this circle,consider one half in which d length of chord is given 16cm, here a right tr. is formed wid hypot=rad=17cm, base=8cm(perp from d centre bisects d chord). let d perp=x cm. by pythagor. thm, (17sqr)=8 sqr+x sqr this implies x=15cm the distance btw d chords is 23cm this implies d other part is 23-x cm= 8cm in the other half circle, see the rt trangle, wid perp=8cm,hypot=17cm, apply the pythagoras thm 2 get the base =15cm again apply the result that perp from the centre bisects the chord . this implies length of chord=2(15)=30cm.

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Ranjita asks : An astronmical telescope has an objective of focal length 200 cm and an eyepiece of focal length 10 cm . An observer ajusts the distance of the eyepiece from the objective to obtain the image of the sun on a screen 40 cm behind the eyepiece. The diameter of the sun’s image is 6.0 cm .Find the diameter of the sun. The average earth-sun distance is 1.5x 1011 m.

Tag : focal,obtain,image,telescope,eyepiece,earthsun,screen,objective,length,observer

Category : Class XI / XII | On : 2012-01-17 03:29:22

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Gagandeep kaur asks : two communicating cylindrical tubes contain mercury. the diameter of one vessel is four times larger than the diameter of the other. a column of water of height 70 cm is poured into the narrow vessel. how much will the mercury level rise in the other vessel and how much will it sink in the narrow one? how much will the mercury level rise in the narrow vessel, if a column of water of the same height is poured into the broad vessel?