Pakistan MCQs

Chemical reactions inside a battery create an electric potential.
The stored chemical energy is converted into electrical energy.

Solar cells use the photovoltaic effect.
They convert light directly into electrical energy.

A microphone detects sound vibrations.
It converts them into corresponding electrical signals.

A loudspeaker uses electrical signals to move a diaphragm.
The diaphragm produces sound waves in air.

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.

Water exerts an upward buoyant force on immersed objects.
Floating occurs when this force balances the object's weight.

Archimedes' principle relates buoyant force to displaced fluid.
The upward force equals the weight of the displaced fluid.

Average speed is total distance divided by total time.
Thus, 120 ÷ 2 = 60 km/h.

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

Gravity attracts masses toward one another.
Near Earth, it pulls objects toward the ground.