Each question consists of two statements, namely, Assertion (A) and Reason (R). For selecting the correct answer, use the following code:
Assertion (A): A hemisphere of radius 7 cm is to be painted outside on the surface. The total cost of painting at Rs 5 per cm2 is Rs 2300.
Reason (R): The total surface area of a hemisphere is 3πr2.
Assertion is wrong and Reason is correct.
Explanation:
Assertion (A):
Given: A hemisphere of radius 7 cm.
Total surface area of the hemisphere is: 3πr2
Let S be the TSA of the hemisphere.
∴ S = 3πr2 = 3π(7)2
∴ S = 462cm2
The total cost to pain it: 462 × 5 = Rs 2310
Reason(R):
The total surface area of a hemisphere is 3πr2.
∴ Assertion is wrong and Reason is correct.