Physics

• What is the gravitational field strength on Earth?

  1. 8 Newtons per kilogram
• How is kinetic energy calculated?

  Kinetic energy is equal to $\frac{1}{2} m v^2$.
• What unit is used for energy?

  Joule
• What does the equation $E_p =$$m g h$ represent?


  It represents gravitational potential energy.
• What is the formula for thermal energy change?

  $Q =$$m c \Delta \Theta$
• What does the specific heat capacity represent?

  It is the amount of energy required to raise the temperature of 1 kilogram of a substance by 1°C.
• What are the four main energy transfer processes?

  Heating, electrical, mechanical, and radiation.
• How is power defined in physics?

  Power is the rate at which energy is transferred or work is done.
• What is the formula for calculating power?

  $P =$$\frac{E}{t}$
• What does efficiency measure?

  Efficiency measures the ratio of useful output energy transfer to total input energy transfer.
• What are non-renewable energy resources?

  Coal, oil, gas, and nuclear fuels.
• How do wind turbines generate electricity?

  They convert the power of the wind into mechanical energy to turn a generator.
• What is the role of a light-dependent resistor (LDR)?

  It changes resistance based on light intensity.
• What happens to the current in a series circuit?

  The current is the same at all points in the circuit.
• How does current behave in a parallel circuit?

  The total current is the sum of the currents through each branch.
• What is the relationship between potential difference and current in a resistor?

  V = I * R
• What happens to the resistance of a filament lamp as it heats up?

  The resistance increases as the temperature rises.
• What is the formula for electrical power?

  $P =$$V \cdot I$
• What are the characteristics of series and parallel circuits?

  • Series Circuit:
  • Same current throughout
  • Total resistance is the sum of individual resistances
  • Potential difference is split across components

  
  

  • Parallel Circuit:
  • Current splits at junctions
  • Total current is the sum of currents through each branch
  • Potential difference is the same across each branch
• What are the differences between ohmic conductors, filament lamps, and diodes?

  • Ohmic Conductors:
  • Current is proportional to potential difference
  • Resistance remains constant

  
  

  • Filament Lamps:
  • Resistance increases with temperature
  • Non-linear relationship between current and potential difference

  
  

  • Diodes:
  • Allow current to flow in one direction only
  • Current is zero for negative potential difference
• What are the different energy stores and their definitions?

  • Kinetic Energy: Energy due to motion
  • Elastic Potential Energy: Energy stored when an object is deformed
  • Gravitational Potential Energy: Energy due to height
  • Thermal Energy: Internal energy of a substance
• What are the methods of generating electricity from renewable resources?

  • Wind Turbines: Convert wind energy to mechanical energy
  • Solar Cells: Convert sunlight directly to electricity
  • Hydro, Wave, and Tidal: Use moving water to turn turbines
  • Geothermal: Utilize heat from the Earth
• What is the significance of efficiency in energy transfer?

  • Efficiency indicates how much input energy is converted to useful output energy.
  • Higher efficiency means less energy wasted.
  • Efficiency can be calculated as useful output energy / total input energy.
• What are the key components of an electrical circuit?

  • Power Supply: Provides energy
  • Ammeter: Measures current (in series)
  • Voltmeter: Measures potential difference (in parallel)
  • Resistors: Control current flow
• What is the role of circuit symbols in electrical circuits?

  • Circuit symbols represent different components.
  • They simplify the drawing of circuits.
  • Familiarity with symbols is essential for understanding circuit diagrams.
• What is the relationship between charge, current, and time in a circuit?

  • Charge (Q) is the product of current (I) and time (T).
  • Formula: $Q =$$I \cdot T$
  • Charge is measured in coulombs, current in amps, and time in seconds.
• What happens to the total resistance in a series and parallel circuit?

  • Series Circuit: Total resistance is the sum of individual resistances.
  • Parallel Circuit: Total resistance is less than the smallest individual resistance.
• How does the potential difference behave in series and parallel circuits?

  • Series Circuit: Potential difference is split across components.
  • Parallel Circuit: Potential difference is the same across each branch.
• How does the total resistance in a series circuit change with the addition of more resistors?

  The total resistance increases with the addition of more resistors.
• What happens to the total resistance in a parallel circuit when more resistors are added?

  The total resistance decreases with the addition of more resistors.
• What is the relationship between total resistance in a parallel circuit and the individual resistances R1 and R2?

  The total resistance is less than both R1 and R2.
• What is electrical power and how is it calculated?

  • Electrical power is the amount of energy transferred per second.
  • It is calculated using the formula:

  $P =$$V \times I$

  where P is power in Watts, V is potential difference in Volts, and I is current in Amps.
• How is energy transferred in terms of power and time?

  Energy is equal to power multiplied by time.
• What is the formula for calculating power using current and resistance?

  The formula is $P =$$I^2 R$.
• What is the unit of energy when calculated from charge and potential difference?

  Energy is measured in Joules.
• What is the frequency of the UK mains electricity supply?

  The frequency is 50 cycles per second.
• What are the three wires in a typical three-core cable?

  The three wires are brown (live), blue (neutral), and green/yellow (earth).
• What is the purpose of the earth wire in a circuit?

  The earth wire provides a safe path for electricity to flow back to the ground in case of a fault.
• What is the National Grid and how does it function?

  • The National Grid is a system of cables and transformers linking power stations to consumers.
  • It uses transformers to step up voltage for transmission and step down voltage for safe use.
• What happens in a transformer when there is an alternating supply?

  It induces an alternating supply in the secondary coil, allowing voltage to be increased or decreased.