O-Level Combined Science — Physics 3

Question 1

What is the relationship between pressure and depth in a liquid?

Accepted Answer

Pressure increases with depth

Answer

Pressure in a liquid increases with depth because the weight of liquid above increases. P = ρgh.

Question 2

Which type of electromagnetic radiation has the longest wavelength?

Accepted Answer

Radio waves

Answer

Radio waves have the longest wavelength in the electromagnetic spectrum, ranging from 1 mm to over 100 km.

Question 3

A pendulum completes 20 oscillations in 10 seconds. What is its frequency?

Accepted Answer

2 Hz

Answer

Frequency = number of oscillations ÷ time = 20 ÷ 10 = 2 Hz.

Question 4

What is the unit of electrical resistance?

Accepted Answer

Ohm

Answer

The unit of electrical resistance is the Ohm (Ω), defined by Ohm's Law: V = IR.

Question 5

Which mirror produces a virtual, upright, and diminished image?

Accepted Answer

Convex mirror

Answer

A convex mirror always produces a virtual, upright, and diminished (smaller) image, regardless of object position.

GCE O-Level Practice Test