Free GED Science Physical Science Practice Test Flashcards

What is the SI unit of force?

Answer: Newton

The SI unit of force is the Newton (N), named after Isaac Newton. 1 Newton = 1 kg·m/s².

Which of Newton's Laws states that an object in motion stays in motion unless acted upon by an external force?

Answer: Newton's First Law (Inertia)

Newton's First Law of Motion states that an object at rest stays at rest, and an object in motion stays in motion, unless acted upon by a net external force — this is the law of inertia.

What happens to the temperature of water when it boils at 100°C and becomes steam?

Answer: The temperature stays constant during the phase change

During a phase change (like boiling), energy is used to break intermolecular bonds rather than increase temperature. The temperature remains constant at 100°C until all the water has turned to steam.

What is the formula for calculating work?

Answer: W = F × d

Work = Force × distance (W = Fd). Work is measured in Joules (J).

Which of the following is a chemical change (not a physical change)?

Answer: Wood burning

Burning wood is a chemical change — it produces new substances (ash, CO₂, water vapor) through a chemical reaction. The other options are physical changes.

What is the atomic number of an element?

Answer: The number of protons in the nucleus

The atomic number is the number of protons in an atom's nucleus. It uniquely identifies the element and determines its position on the periodic table.

Which type of wave requires a medium to travel?

Answer: Sound waves

Sound waves are mechanical waves that require a medium (solid, liquid, or gas) to travel through. Electromagnetic waves (light, radio, X-rays) can travel through a vacuum.

Ohm's Law states that voltage (V) equals:

Answer: Current × Resistance (V = IR)

Ohm's Law: V = IR, where V is voltage (volts), I is current (amperes), and R is resistance (ohms).

What is the law of conservation of energy?

Answer: Energy cannot be created or destroyed, only converted from one form to another

The law of conservation of energy states that energy cannot be created or destroyed — it can only be transformed from one form (kinetic, potential, thermal, etc.) to another.

An atom has 17 protons, 18 neutrons, and 17 electrons. What is its atomic mass?

Answer: 35

Atomic mass = protons + neutrons = 17 + 18 = 35. (This is the element chlorine, Cl-35.)

Which of the following best describes a conductor?

Answer: A material that allows electric current to flow easily

A conductor is a material (like copper or aluminum) that allows electric charges to move freely, enabling the flow of electric current.

What is the difference between a physical change and a chemical change?

Answer: Physical changes alter the form of a substance without changing its chemical composition; chemical changes produce new substances

Physical changes (melting, freezing, cutting) change the form or appearance without altering chemical composition. Chemical changes (burning, rusting, cooking) produce new substances with different chemical properties.

A 5 kg object is accelerated at 3 m/s². What is the net force acting on it?

Answer: 15 N

F = ma = 5 kg × 3 m/s² = 15 N.

Which of the following is an example of potential energy?

Answer: A book resting on a high shelf

Potential energy is stored energy based on position or condition. A book on a high shelf has gravitational potential energy due to its position above the ground.

What type of bond forms when one atom completely transfers an electron to another atom?

Answer: Ionic bond

An ionic bond forms when one atom completely transfers one or more electrons to another, creating oppositely charged ions that attract each other.

The Periodic Table organizes elements primarily by:

Answer: Increasing atomic number

The modern Periodic Table arranges elements in order of increasing atomic number (number of protons), with rows (periods) and columns (groups) reflecting chemical and physical properties.

Which of the following describes the speed of light?

Answer: 300,000 km/s

The speed of light in a vacuum is approximately 300,000 km/s (or 3 × 10⁸ m/s).

What is the difference between an acid and a base?

Answer: Acids donate protons (H⁺ ions); bases accept protons

According to the Brønsted-Lowry definition, acids donate hydrogen ions (H⁺) and bases accept them. Acids have pH below 7; bases have pH above 7.

In a chemical equation, what does the Law of Conservation of Mass require?

Answer: The number of atoms on both sides of the equation must be equal

The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. The total number of atoms of each element must be the same on both sides of the balanced equation.

Which subatomic particle has a negative charge?

Answer: Electron

Electrons have a negative charge (-1). Protons have a positive charge (+1). Neutrons have no charge (0).