A hollow spherical shell is made of a metal of density 36 g/cm³. Its internal and external radius are 1 cm and 2 cm, respectively. What is the weight (in kg) of the shell ? $$(take \pi = \frac{22}{7})$$​​

Correct option is B

Given:

Density of metal = 36 g/cm³

Internal radius = 1 cm

External radius = 2 cm

Formula Used:

Volume of spherical shell 

V $$= \frac{4}{3}\pi (R^3 - r^3)$$​

Mass = Volume × Density

Solution :

$$V = \frac{4}{3} \times \frac{22}{7} \times (2^3 - 1^3) \\ \ \\= \frac{4}{3} \times \frac{22}{7} \times (8 - 1) \\ \ \\= \frac{4}{3} \times \frac{22}{7} \times 7 \\ \ \\= \frac{4}{3} \times 22 = \frac{88}{3} \, \text{cm}^3$$​

Mass $$= \frac{88}{3} \times 36 = 1056 \, \text{g}$$​​

Weight =$$\frac{1056}{1000} = 1.056 \, \text{kg}$$​​