Question
Why are small gaps left between the metal rails of a railway track?
A to allow for expansion of the rails on a hot day
B to allow for contraction of the rails on a hot day
C to allow for expansion of the rails on a cold day
D to allow for contraction of the rails on a cold day
Answer/Explanation
Ans: A
Question
On a cold day, a metal measuring tape graduated in millimetres is used to measure the distance between two fence posts. The measuring tape reads 3.000 m.
On a much hotter day, the metal measuring tape is used to measure the length of the same distance again. The metal measuring tape has a higher temperature than the ground. The temperature of the ground remains constant.
Which statement is correct?
The measuring tape reads less than 3.000 m because the graduations are closer together.
The measuring tape reads less than 3.000 m because the graduations are further apart.
The measuring tape reads more than 3.000 m because the graduations are closer together.
The measuring tape reads more than 3.000 m because the graduations are further apart.
Answer/Explanation
Ans: B
Question
What happens when a metal block is heated?
- Its breadth, height and length all increase.
- Its width increases only.
- Its height increases only.
- Its length increases only.
Answer/Explanation
Ans: A
Question
Which quantity does not change when there is an increase in temperature?
the density of a steel block
the diameter of the hole in a metal nut
the length of an iron rod
the mass of a metal coin
Answer/Explanation
Ans: D
All the properties like density, volume, length , diameter of solids depends upon temperature.
It may increase or decrease with change in temperature
Question
A wooden wheel can be strengthened by putting a tight circle of iron around it.
Which action would make it easier to fit the circle over the wood?
cooling the iron circle
heating the iron circle
heating the wooden wheel and cooling the iron circle
heating the wooden wheel but not heating or cooling the iron circle
Answer/Explanation
Ans: B
For fixing the metal rim on a wooden wheel of a cart, the metal rim is made slightly smaller than the wooden wheel. On heating, the rim expands and fits onto the wheel.