Question

Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): There are two atoms per unit cell in bcc.
Reason (R): A body-centred cubic (bcc) unit cell has an atom at each of corners and also one atom at its body centre.

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is not the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Answer 1

The correct option is A Both A and R are true and R is the correct explanation of A

A body-centred cubic (bcc) unit cell has an atom at each of corners and also one atom at its body centre.
So effective number of atoms per unit cell $=\frac{1}{8}\times 8+1=2$