A cube and a sphere of the same material and same total surface area are placed in the sae space turn by turn, after heating them to the same temperature. Compare their initial rate of cooling in the enclosure.
1 Answers
Finely divided catalyst has greater surface area and has greater catalytic activity than the compact solid. If a total surface area of 6291456 `cm^(2)
Correct Answer - C Total Surface area of eight cubes `=8xx6xx(1/2xx1/2)^2` Apply the formula Surface area on n split of a cube `=8^nxx6xx(1/2)^(2n)` `6291456=8^n xx 6 xx (1/2)^(2n)`
2 Answers 1 views
Two dice are thrown together and the total score is noted. The event E, F and G are a total 4, a total of 9 or more, and a total divisible by 5, respe
Two dices are thrown together i.e., sample spaces (S) =36`rArr`n(S)=36 E=A total of 4 = {(2,2),(3,1),(1,3)} `rArr n(E )=3` F= A total of 9 or more `={(3,6),(6,3),(4,5),(4,6),(5,4),(6,4),(5,5),(5,6),(6,5),(6,6)}` `rArr n(F)=10` G...
2 Answers 1 views
A hollow copper sphere & a hollow copper cube of same surface area & negligible thickness , are filled with warm water of same temperature and placed
Correct Answer - B::D For surface areas to be same `S_("sphere") = S_("cube") implies 4piR^(2) = 6a^(2) implies (a)/(R) = sqrt((2pi)/(3)) (gt1`) Volume ratio ` (V_("sphere"))/(V_("cube")) = ((4)/(3)piR^(3))/(a^(3)) = (2R)/(a) =...
2 Answers 4 views
In a sphere of radius r, a right circular cone of height h having maximum curved surface area is inscribed area is inscribed.
Option : (c) 2π2r (2rh2 - h3)
2 Answers 6 views
What will be the total flux through the faces of the cube, with side of length a if a charge q is placed at (a) A : a corner of the cube (b) B : mid-p
(a). There are eight corners in a cube so, total charge for the cube is `(q)/(8)`. ltbr. Thus, electric flux at `A=(q)/(8epsi_(0))` ltb rgt (b) When the charge q is...
2 Answers 1 views
The inner surface of the wall of a sphere is perfectly reflecting. Radius of the sphere is R. A point source S is placed at a distance `R//2` from the
Correct Answer - At a distance `(5R)/(6)` from the nearest wall
2 Answers 2 views
A uniformly charged sphere carries a total charge of `2 pi xx10^(-12)` C. Its radius is 5 cm and is placed in vacuum. Determine its surface charge den
Correct Answer - `2xx 10^(-10)Cm ^(2)`
2 Answers 1 views
Consider three identical metal spheres ` A, B` and `C`. Sphere `A` carries charge ` + 6q`, sphere `B` carries charge `-3q` and sphere `C` carries no c
Correct Answer - `2.25q`
2 Answers 4 views
An object is placed `50 cm` from the surface of a glass sphere of radius `10 cm` along the diameter. Where will the final image be formed after refrac
Correct Answer - At 20 m from the centre of the sphere
2 Answers 3 views
The volume of a sphere (V) varies directly as the cube of its radius. The volume of the sphere of radius 3 cm is ` 36 pi cm^(3)`. What is the volume o
Correct Answer - ` 4500 pi cm^(3)`
2 Answers 1 views