General Certificate of Secondary Education (GCSE) Combined Science Flashcards

24 sample cards from the Combined Science deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. State the equation for kinetic energy and define each term.

   $$E_k = \frac{1}{2}mv^{2}$$ where $E_k$ is kinetic energy in joules (J), $m$ is mass in kilograms (kg) and $v$ is speed in metres per second (m/s).

2. State the equation for gravitational potential energy.

   $$E_p = mgh$$ where $m$ is mass (kg), $g$ is gravitational field strength ($\approx 9.8\ \text{N/kg}$) and $h$ is height (m).

3. How do you calculate the efficiency of an energy transfer?

   $\text{efficiency} = \dfrac{\text{useful output energy transfer}}{\text{total input energy transfer}}$ (can be $\times 100$ for a percentage). Power may be used in place of energy.

4. What is the difference between a scalar and a vector quantity? Give two examples of each.

   A scalar has magnitude only (e.g. speed, mass, distance, energy). A vector has both magnitude and direction (e.g. velocity, force, acceleration, displacement).

5. State Newton's three laws of motion.

   1st: an object stays at rest or at constant velocity unless acted on by a resultant force. 2nd: $F = ma$ (resultant force = mass × acceleration). 3rd: when two objects interact, they exert equal and opposite forces on each other.

6. Give the equation linking force, mass and acceleration.

   $$F = ma$$ where $F$ is resultant force (N), $m$ is mass (kg) and $a$ is acceleration (m/s$^2$).

7. Write the equation for weight and state the value of gravitational field strength on Earth.

   $$W = mg$$ where $W$ is weight (N), $m$ is mass (kg) and $g$ is gravitational field strength, about $9.8\ \text{N/kg}$ on Earth.

8. Define speed, velocity and acceleration.

   Speed is distance travelled per unit time (scalar). Velocity is speed in a given direction (vector). Acceleration is the change in velocity per unit time, $a = \dfrac{\Delta v}{t}$.

9. State the equation for acceleration and the uniform-acceleration (suvat) equation linking velocity and distance.

   $a = \dfrac{v - u}{t}$, and $$v^{2} = u^{2} + 2as$$ where $u$ is initial velocity, $v$ final velocity, $a$ acceleration and $s$ distance.

10. What does the gradient and the area under a velocity-time graph represent?

    The gradient (slope) of a velocity-time graph represents acceleration; the area under the line represents the distance travelled (displacement).

11. State Ohm's law equation linking potential difference, current and resistance.

    $$V = IR$$ where $V$ is potential difference (volts), $I$ is current (amperes) and $R$ is resistance (ohms, $\Omega$).

12. How do current, potential difference and resistance behave in a series circuit?

    Current is the same at all points. Potential difference is shared between components and adds up to the supply p.d. Total resistance is the sum of individual resistances: $R_{total} = R_1 + R_2 + \dots$

13. How do current and potential difference behave in a parallel circuit?

    Potential difference is the same across each branch. The total current is the sum of the currents through the separate branches. Adding resistors in parallel decreases the total resistance.

14. Give the two equations for electrical power.

    $$P = VI \qquad \text{and} \qquad P = I^{2}R$$ where $P$ is power (W), $V$ is potential difference (V), $I$ is current (A) and $R$ is resistance ($\Omega$).

15. State the equation for charge in terms of current and time.

    $$Q = It$$ where $Q$ is charge (coulombs, C), $I$ is current (A) and $t$ is time (s).

16. Describe the arrangement, movement and energy of particles in solids, liquids and gases.

    Solid: particles closely packed in a regular pattern, vibrate in fixed positions, lowest energy. Liquid: close together but random, can move/flow around each other. Gas: far apart, random, move quickly in all directions, highest energy.

17. State the equation for density and give the units.

    $$\rho = \frac{m}{V}$$ where $\rho$ is density (kg/m$^3$), $m$ is mass (kg) and $V$ is volume (m$^3$).

18. What is specific latent heat, and what is the equation for energy in a change of state?

    Specific latent heat is the energy needed to change the state of $1\ \text{kg}$ of a substance with no temperature change. $$E = mL$$ where $E$ is energy (J), $m$ is mass (kg) and $L$ is the specific latent heat (J/kg).

19. Describe the rules for magnetic poles and how to identify a magnetic field direction.

    Like poles repel, unlike poles attract. Magnetic field lines run from north to south outside the magnet; the field is strongest where the lines are closest together (at the poles).

20. Distinguish between transverse and longitudinal waves and give an example of each.

    In a transverse wave the oscillations are perpendicular to the direction of energy transfer (e.g. light, water waves). In a longitudinal wave the oscillations are parallel to the energy transfer, with compressions and rarefactions (e.g. sound).

21. State the wave speed equation and define each term.

    $$v = f\lambda$$ where $v$ is wave speed (m/s), $f$ is frequency (Hz) and $\lambda$ is wavelength (m).

22. List the electromagnetic spectrum in order of increasing frequency.

    Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays. (Increasing frequency means decreasing wavelength and increasing energy.)

23. Name the three types of nuclear radiation and rank them by ionising power and penetration.

    Alpha ($\alpha$): most ionising, least penetrating (stopped by paper). Beta ($\beta$): moderate (stopped by aluminium). Gamma ($\gamma$): least ionising, most penetrating (reduced by thick lead/concrete).

24. Define the half-life of a radioactive isotope.

    The half-life is the time taken for the number of undecayed nuclei (or the activity/count rate) of a radioactive sample to halve.

What this deck covers

Combined Science flashcards FAQ