Pakistan MCQs

A ship contains large air-filled spaces.
Its total mass spread over its volume gives an average density below water.

Thermal radiation travels as electromagnetic waves.
It does not require a material medium.

Density compares mass with the space occupied.
It is calculated as mass divided by volume.

Space between the Sun and Earth is nearly a vacuum.
Solar energy reaches Earth as electromagnetic radiation.

Ice has an open crystal structure that occupies more volume.
Its lower density causes it to float on water.

Wood and many plastics conduct heat poorly.
They reduce heat transfer to the user's hand.

Freezing expands water into a less dense solid structure.
The resulting ice is buoyant in liquid water.

Metals transfer heat efficiently from the flame to food.
This makes cooking faster and more even.

Pressure is force distributed over an area.
The same force produces greater pressure on a smaller area.

A sharp edge concentrates force over a small area.
This creates greater pressure and makes cutting easier.

Pressure is measured in pascals.
One pascal equals one newton per square metre.

Pascal's law states that pressure applied to a confined fluid is transmitted equally.
This allows force multiplication in hydraulic brakes.