Viva Voce: Surface Area of a Cylinder - Class 10 PDF Download

Q.1. What is total surface area of a cylinder?

2πr(r + h)

Q.2. What is the area of a circular face of cylinder?

πr²

Q.3. What is the total area of circular faces of a cylinder?

2πr²

Q.4. What will be the curved surface area of a cylinder if its height is equal to the diameter of the base?

4πr²

Q.5. What is curved surface area of a cylinder?

2πrh

Q.6. Write the number of circular faces of a cylinder?

2

Q.7. If h = 7 cm and r=2 cm, find the lateral surface area of a cylinder.

2πrh =2 ×  227  × 2 × 7 =  88 cm³

Q.8. What will be the curved surface area of a cylinder if its height is 3 times of its radius?

6πr²

Q.9. The radius of a cylinder is 5 inches and the height of the cylinder is 15 inches. Find the surface area of the cylinder. (Take the value of pi as 3.14)

Radius, r = 5 in
Height of the cylinder, h = 15 in
Surface Area of cylinder is: A = 2πr(r+h)
= 2π × 5 × (5 + 15)
= 2π × 5 × 20
= 2 × 3.14 × 5 × 20
= 628
Therefore, the surface area of the cylinder is 628 square inches.

Q.10. Samuel has a cylinder of surface area 1728π square units. Find the height of the cylinder if the radius of the base of the circle is 24 units.

The surface area of the cylinder, A = 1728π; radius (r) = 24; h = ?
Let us substitute the given values in the formula to find the height of the cylinder.
A = 2πr(r + h)
1728π = 2π × 24 × (24 + h)
⇒ 1728/48 = (24 + h)
⇒ 36 = (24 + h)
⇒ h = 12
Therefore, the height of the cylinder is 12 units.