Each question consists of two statements, namely, Assertion (A) and Reason (R). For selecting the correct answer, use the following code:
Assertion (A): If the volumes of two sphere are in the ratio 27:8 then their surface areas are in the ratio 3:2
Reason (R): Volume of a sphere .
Surface area of a sphere = 4πR2.
Assertion is wrong and Reason is Wrong.
Explanation:
Assertion (A):
Given: volumes of two sphere are in the ratio 27:8.
Volume of the sphere is given by: πr3
Let V1 be the volume of the first sphere.
Let V2 be the volume of the first sphere.
∴ V1:V2 = π(r1)3 :
π(r2)3
⇒ 27:8 = (r1)3 : (r2)3
⇒ r1 : r2 = 3:2
Surface area of the sphere is given by: 4πr2
Let S1 be the Surface area of the sphere.
Let S2 be the Surface area of the sphere.
∴ S1 : S2 = 4π(r1)2:4π(r2)2
⇒ S1 : S2 = (r1)2: (r2)2
⇒S1 : S2 = (3)2: (2)2
⇒S1 : S2 = 9:4
Reason(R):
Volume of a sphere = πr3.
Surface area of a sphere = 4πR2.
Assertion is wrong and Reason is Wrong.