05. Factors influencing choice of material 2

Multiple Choice

These cubes of Mild Steel and Copper are the same size. Which one is the heaviest?

• Mild Steel

• Copper

• Both are the same weight

• Neither, they are both light

Multiple Choice

If a 5m length of brass has its temperature increased by 30°K, by how much will it expand? (Given: α = 18 x 10⁻⁶)

• 2.7 x 10⁻³ m

• 2.7 x 10⁻² m

• 1.8 x 10⁻³ m

• 1.8 x 10⁻² m

Multiple Choice

What is the change in length of a metal rod with an initial length of 2 meters, a coefficient of thermal expansion 0.00002 /K, and a temperature change of 20 K?

• 0.0008 meters

• 0.0004 meters

• 0.0002 meters

• 0.0012 meters

Multiple Choice

A steel rail is 24.4m long. How much does it expand during a day when the low temperature is 291°K and high temperature is 306°K? (Steel = $$15 \times 10^{-6}$$ )

• 0.00549 m

• 0.00366 m

• 0.00732 m

• 0.00459 m

Multiple Choice

A length of a brass bar is 150 cm at 40°C. What will be its length at 100°C? (α = 18 x 10⁻⁶ /K)

• 150.162 cm

• 150.108 cm

• 150.324 cm

• 150.216 cm

Multiple Choice

An aluminium flag pole is 20.0 m tall on a -15°C winter’s day. How much higher will the flag fly from the pole on a hot 42°C summer day? (α = 23 x 10⁻⁶)

• 0.026 m

• 0.032 m

• 0.018 m

• 0.045 m