Question

For the orthorhombic system, axial ratios are $\mathrm{a}\ne \mathrm{b}\ne \mathrm{c}$, and the axial angles are:

• A. $\mathrm{\alpha }=\mathrm{\beta }=\mathrm{\gamma }\ne 90$ degree
• B. $\mathrm{\alpha }=\mathrm{\beta }=\mathrm{\gamma }=90$ degree
• C. $\mathrm{\alpha }\ne \mathrm{\beta }=\mathrm{\gamma }=90$ degree
• D. $\mathrm{\alpha }\ne \mathrm{\beta }\ne \mathrm{\gamma }=90$degree

Answer 1

The correct option is B

$\mathrm{\alpha }=\mathrm{\beta }=\mathrm{\gamma }=90$ degree

Explanation for the Correct Option:

Option(B):$\mathrm{\alpha }=\mathrm{\beta }=\mathrm{\gamma }=90$ degree

• In the orthorhombic system, axial ratios are given as: $\mathrm{a}\ne \mathrm{b}\ne \mathrm{c}$and the axial angles are $\mathrm{\alpha }=\mathrm{\beta }=\mathrm{\gamma }=90°$.
• This shows all the three edge lengths are unequal but all the angles are equal and are equal to $90°$.
  

Explanation for the inCorrect Option:

Option(A):$\mathrm{\alpha }=\mathrm{\beta }=\mathrm{\gamma }\ne 90$ degree

• The Option states that, in an Orthorhombic crystal lattice, all the bond angles are equal also they are not equal to $90°$.
• Hence, the given Option does not coincide with the correct option.

Option(C):$\mathrm{\alpha }\ne \mathrm{\beta }=\mathrm{\gamma }=90$ degree

• In the orthorhombic system, all the angles are equal and are equal to $90°$.
• Hence, the option is an incorrect one.

Option(D):$\mathrm{\alpha }\ne \mathrm{\beta }\ne \mathrm{\gamma }=90$degree

• The Option states that, in an Orthorhombic crystal lattice, all the bond angles are not equal but they are equal to $90°$.
• Hence, the given Option does not represent to the correct Concept.

Therefore, For the orthorhombic system, axial ratios are $\mathrm{a}\ne \mathrm{b}\ne \mathrm{c}$, and the axial angles are: $\mathrm{\alpha }=\mathrm{\beta }=\mathrm{\gamma }=90$ degree .