Heat and Thermodynamics - SS2 Physics Past Questions and Answers - page 3
Which of the following materials typically expands the most when heated?
Wood
Steel
Aluminium
Glass
When an object undergoes thermal expansion, what happens to its density?
It decreases
It increases
It remains constant
It depends on the material
Which of the following statements is true regarding the coefficient of linear expansion (α) of a material?
It is always negative
It is different for every material
It depends on the temperature
It is constant for a given material
Which of the following objects would experience the greatest expansion when heated by the same amount?
A solid metal bar
A hollow metal sphere
A solid wooden block
A hollow glass tube
A steel rod has an original length of 2 metres. If its coefficient of linear expansion is 12 × 10-6 /°C and it is heated by 100°C, what will be its new length?
ΔL = α x L x ΔT = (12 × 10-6 /°C) x (2 metres) x (100°C) = 0.024 metres
New length = Original length + ΔL = 2 metres + 0.024 metres = 2.024 metres
Users' Answers & CommentsA copper pipe with an original length of 5 metres is heated from 20°C to 80°C. If the coefficient of linear expansion for copper is 16 × 10^-6 /°C, what is the change in length of the pipe?
ΔL = α x L x ΔT = (16 × 10^-6 /°C) x (5 metres) x (80°C - 20°C) = 0.032 metres
Users' Answers & CommentsA glass container has an original volume of 500 cm^3 at 25°C. If the coefficient of volume expansion for glass is 9 × 10^-6 /°C and it is heated to 75°C, what will be its new volume?
ΔV = β x V x ΔT = (9 × 10^-6 /°C) x (500 cm3) x (75°C - 25°C) = 0.15 cm3
New volume = Original volume + ΔV = 500 cm3 + 0.15 cm3 = 500.15 cm3
Users' Answers & CommentsA brass ring with an original diameter of 8 cm is heated from 20°C to 100°C. If the coefficient of linear expansion for brass is 19 × 10^-6 /°C, what will be its new diameter?
ΔD = α x D x ΔT = (19 × 10^-6 /°C) x (8 cm) x (100°C - 20°C) = 0.136 cm
New diameter = Original diameter + ΔD = 8 cm + 0.136 cm = 8.136 cm
Users' Answers & CommentsAccording to the first law of thermodynamics, the change in internal energy of a system is equal to:
The heat added to the system minus the work done by the system.
The heat added to the system plus the work done by the system.
The heat added to the system multiplied by the work done by the system.
The heat added to the system is divided by the work done by the system.
The second law of thermodynamics states that:
Energy cannot be created or destroyed, only transferred or transformed.
The entropy of a system always increases over time.
The temperature of a system always decreases over time.
The pressure of a system always decreases over time.