Question

9.
The coefficient of linear expansion of a crystalline
substance in one direction is 2 x 10-41°C and in
every direction perpendicular to it is 3 * 10-4/°C.
The coefficient of cubical expansion of crystal is
equal to
(1) 5 x 10-41°C
(2) 4 x 10-41°C
(3) 8 x 10-41°C
(4) 7 * 10-41°C​

Answer 1

Answer:

c

Explanation:

The cubical expansion of the crystal is equal to the sum of coefficient of linear expansions in three mutually perpendicular directions. y= Ax + Ay + Az = 2 x 10-4 + 3 x 10-4 + 3 x 10-4 = 8 x 10-41    

Answer 2

The coefficient of cubical expansion of crystal is  equal to (3) 8 x 10⁻⁴ /°C

Explanation:

The cubical expansion of the crystal is equal to the sum of coefficient of linear expansions in three mutually perpendicular directions.

Now, the coefficient of cubical expansion is given as:

γ = αx + αy + αz

One direction is parallel and other two directions are in perpendicular direction.

γ = (2 × 10⁻⁴) + (3 × 10⁻⁴) + (3 × 10⁻⁴)

γ = (2 + 3 + 3) × 10⁻⁴

∴ γ = 8 × 10⁻⁴ /°C