A cylindrical metallic wire is stretched to double its length. Which of the following will NOT change for the wire after stretching?

1. Its curved surface area

2. Its total surface area

3. Its volume

4. Its radius

A right circular cone has the radius of the base equal to the height of the cone. If the volume of the cone is 9702 cu. cm, then the diameter of the base of the cone is :

1. 21 cm

2. 42 cm

3. $21\sqrt{7}$ cm

4. $2\sqrt{7}$ cm

$\Big[\text{Use } \pi = \dfrac{22}{7}\Big]$

Two identical solid hemispheres are kept in contact to form a sphere. The ratio of the total surface areas of two hemispheres to the surface area of the sphere formed is :

1. 1 : 1

2. 3 : 2

3. 2 : 3

4. 2 : 1

cosec² θ + sec² θ is equal to :

1. tan² θ + cot² θ

2. cot θ + tan θ

3. (cot θ + tan θ)²

4. 1