Sphere and its surface area

Q.

What all are preserved under rotation?

1. Collinearity

2. Parallelism

3. Concurrence

4. Area

Q.

What is the diameter (in cm) of a sphere whose surface area is 616${\text{cm}}^2$?

1. 28

2. 21

3. 7

4. 14

Q.

Match the object in Column A to formulae in Column B. Choose the Option with correct matches.

$$\begin{array}{cc}A& B\\ 1.Surfaceareaofcone& 1.4\pi r^2\\ 2.Surfaceareaofsphere& 2.2\pi rh\\ 3.curvedsurfaceareaofcylinder& 3.\pi rL\end{array}$$

1. A1-B3, A2-B1, A3-B2

2. A1-B3, A2-B2, A3-B1

3. A1-B2, A2-B1, A3-B3

4. A1-B1, A2-B2, A3-B3

Q.

Ram has a semicircular disc. He rotates it about its diameter by 360 degrees. When he rotates the disc, a volume of air in his room gets swept. What is the name of the object/shape that exactly occupies this volume?

1. Hemisphere

2. Cone

3. Cylinder

4. Sphere