GCSE Combined Science Physics

Question 1

What is the unit of measurement for electrical resistance?

Accepted Answer

Ohms (Ω)

Answer

Resistance is measured in ohms (Ω), named after Georg Ohm. Resistance is the opposition to the flow of current in a circuit. It can be calculated using Ohm's Law: R = V ÷ I (resistance = voltage ÷ current).

Question 2

A force of 200 N is applied to an area of 0.5 m². What is the pressure?

Accepted Answer

400 Pa

Answer

Pressure = force ÷ area = 200 ÷ 0.5 = 400 Pa. Pressure is measured in pascals (Pa). A smaller area with the same force creates a greater pressure, which is why sharp objects penetrate more easily.

Question 3

Which type of electromagnetic wave has the shortest wavelength?

Accepted Answer

Gamma rays

Answer

Gamma rays have the shortest wavelength and highest frequency in the electromagnetic spectrum. The order from longest to shortest wavelength is: radio, microwave, infrared, visible light, ultraviolet, X-rays, gamma rays.

Question 4

What is the law of conservation of energy?

Accepted Answer

Energy cannot be created or destroyed, only transferred between stores

Answer

The law of conservation of energy states that energy cannot be created or destroyed — it can only be transferred from one energy store to another. The total energy in a closed system always remains constant.

Question 5

A car accelerates from rest to 20 m/s in 5 seconds. What is its acceleration?

Accepted Answer

4 m/s²

Answer

Acceleration = change in velocity ÷ time = (20 - 0) ÷ 5 = 4 m/s². Starting 'from rest' means the initial velocity is 0 m/s. Acceleration tells us how quickly the velocity is changing.

GCSE Revision Practice Test

GCSE Revision Practice Test

GCSE Combined Science Physics