Key concepts in Physics

• What is the purpose of SI units in measurements?

  To standardize measurements globally
• Why is it important to state the unit of measurement?

  It provides understanding of the measurement scale
• What is the SI unit for length?

  Metre (m)
• What is the SI unit for mass?

  Kilogram (kg)
• What is the SI unit for time?

  Second (s)
• What is the SI unit for electrical current?

  Ampere (A)
• What is the SI unit for temperature?

  Kelvin (K)
• What is the SI unit for the amount of substance?

  Mole (mol)
• What are derived units?

  Units that come from fundamental units
• What is the standard unit for frequency?

  Hertz (Hz)
• What is the SI unit for force?

  Newton (N)
• What is the SI unit for energy?

  Joule (J)
• What is the SI unit for power?

  Watt (W)
• What is the SI unit for pressure?

  Pascal (Pa)
• What is the SI unit for electric charge?

  Coulomb (C)
• What is the SI unit for electric potential difference?

  Volt (V)
• What is the SI unit for electric resistance?

  Ohm (Ω)
• What is the SI unit for magnetic flux density?

  Tesla (T)
• What are the six fundamental SI units?

  • Metre (m) - length
  • Kilogram (kg) - mass
  • Second (s) - time
  • Ampere (A) - electrical current
  • Kelvin (K) - temperature
  • Mole (mol) - amount of substance
• What is the SI unit system called?

  Système Internationale d'Unités
• Why do scientists use standard form?

  To write large or small numbers conveniently
• How would you express $4,400,000,000,000 \text{ m}$ in standard form?


  $4.4 \times 10^{12} \text{ m}$
• How would you express $7,300,000,000,000 \text{ m}$ in standard form?


  $7.3 \times 10^{12} \text{ m}$
• What are the prefixes for the following powers of ten: 12, 9, 6, 3, -2, -3, -6, -9?

  • 12: tera- (T)
  • 9: giga- (G)
  • 6: mega- (M)
  • 3: kilo- (k)
  • -2: centi- (c)
  • -3: milli- (m)
  • -6: micro- (μ)
  • -9: nano- (n)
• What does the prefix 'kilo-' represent in terms of size?

  1,000
• What does the prefix 'milli-' represent in terms of size?

  0.001
• How do you convert $4.4 \times 10^{12} \text{ m}$ to terametres?


  It equals $4.4 \text{ Tm}$
• How do you convert $7.3 \times 10^{12} \text{ m}$ to terametres?


  It equals $7.3 \text{ Tm}$
• What is the conversion of 1,000 metres in terms of kilometres?

  1 km
• Which is larger: 360 kV or 3.6 MV?

  3.6 MV is larger
• How do you convert 360 kV to volts?

  360,000 volts
• How do you convert 3.6 MV to volts?

  3,600,000 volts
• What are the advantages of using unit prefixes in measurements?

  • Simplifies large numbers
  • Reduces writing effort
  • Enhances clarity in communication
• What is the standard unit for electrical power?

  Watts (W)
• Why do scientists state measurements with units?

  To ensure clarity and accuracy
• What is the purpose of unit conversion?

  To express measurements in a more useful form
• How do you convert 50 mA to amperes?

  50 mA = 0.05 A
• What is the formula for calculating electrical power?

  Power = current × voltage
• What is the electrical power when a 50 mA current passes through a 230 V light bulb?

  11.5 W
• How do you convert 12 mV to volts?

  12 mV = 0.012 V