Mathematics
Assertion (A): The radius of a hemisphere increases from r cm to 2r cm. The ratio between the surface area of the original hemisphere and the resulting hemisphere is 1 : 4.
Reason (R): Surface area of the first case = πr2 + 2πr2
Surface area of the second case = π(2r)2 + 2π(2r)2
A is true, but R is false.
A is false, but R is true.
Both A and R are true, and R is the correct reason for A.
Both A and R are true, and R is the incorrect reason for A.
Related Questions
The radius of a cylinder is doubled and its curved surface area is kept as same, the height of the cylinder is:
same
doubled
halved
none of these
Statement 1: Each side of a cuboid is doubled, its total surface area is also doubled.
Statement 2: The surface area of resulting cuboid is 2 x 2 x 2 times the original area.
Both the statements are true.
Both the statements are false.
Statement 1 is true, and statement 2 is false.
Statement 1 is false, and statement 2 is true.
A hollow square-shaped tube open at both ends is made of iron. The internal square is of 5 cm side and the length of the tube is 8 cm. There are 192 cm3 of iron in this tube. Find its thickness.