Question : The radius of a hollow sphere is 21 cm. It is cut into two equal halves by a plane passing through its centre. What is 75% of the curved surface area (in cm², rounded off to the nearest tens) of the hemisphere? (Take $\pi=\frac{22}{7}$ )

Option 1: 4160

Option 2: 3470

Option 3: 2080

Option 4: 2770

Question : What will be the difference between the total surface area and the curved surface area of a hemisphere having a 4 cm diameter in cm²?

Option 1: $5\pi $

Option 2: $8\pi $

Option 3: $4\pi $

Option 4: $4.4\pi $

Question : What is the difference between the total surface area and the curved surface area of a cone whose radius is 35 cm? (Take $\pi=\frac{22}{7}$)

Option 1: 3850 cm²

Option 2: 3704 cm²

Option 3: 3750 cm²

Option 4: 3675 cm²

Question : The curved surface area (CSA) and the total surface area (TSA) of a hemisphere whose radius is 7 cm are:

Option 1: CSA – 350 cm²; TSA – 500 cm²

Option 2: CSA – 320 cm²; TSA – 480 cm²

Option 3: CSA – 412 cm²; TSA – 544 cm²

Option 4: CSA – 308 cm²; TSA – 462 cm²

Question : A sphere is of radius 5 cm. What is the surface area of the sphere?

Option 1: $100 \pi \;\mathrm{cm^2}$

Option 2: $150 \pi \;\mathrm{cm^2}$

Option 3: $200 \pi\;\mathrm{cm^2}$

Option 4: $120 \pi\;\mathrm{cm^2}$

Question : A hemisphere has a 42 cm diameter. Find its curved surface area and the total surface area.

Option 1: 2772 cm² and 4158 cm²

Option 2: 3772 cm² and 5158 cm²

Option 3: 4770 cm² and 4238 cm²

Option 4: 3072 cm² and 4058 cm²