Weak areas

• What is nuclear fission?


  Nuclear fission is the process of splitting a large, unstable atomic nucleus into smaller, more stable nuclei.
• What happens during nuclear fission?


  It releases energy in the form of kinetic energy of the fragments, neutrons, and gamma radiation.
• Which heavy element is commonly associated with nuclear fission?


  Uranium-235
• What are the key points of nuclear fission?


  • Involves splitting of heavy atomic nuclei
  • Results in smaller nuclei
  • Releases energy
  • Typically occurs with heavy elements like uranium-235
• What is the structure of an atom?


  An atom consists of a nucleus containing protons and neutrons, and electrons orbiting the nucleus.
• What determines the element of an atom?


  The number of protons determines the element.
• What are isotopes?


  Isotopes are atoms of the same element with different numbers of neutrons.
• What is the mass number of an atom?


  The mass number is the total number of protons and neutrons in the nucleus.
• In nuclear fission, which part of the atom is split?


  The nucleus.
• What are the steps involved in nuclear fission?


  1. Neutron absorption by a heavy nucleus
  2. Nucleus becomes unstable
  3. Nucleus splits into smaller nuclei
  4. Energy is released
  5. Neutrons are emitted
• What is the key equation for nuclear fission involving uranium-235?


  $^{235}_{92}\text{U} +$$^{1}_{0}\text{n} \rightarrow ^{141}_{56}\text{Ba} +$$^{92}_{36}\text{Kr} +$$3^{1}_{0}\text{n} +$$\text{energy}$
• What is the initial step in nuclear fission?


  A free neutron is absorbed by a heavy nucleus.
• What is a chain reaction in nuclear fission?


  1. Initial fission releases 2-3 neutrons
  2. Released neutrons cause fission in nearby nuclei
  3. Each secondary fission releases more neutrons
  4. The process continues, leading to exponential growth
• Why is it important to control the chain reaction in a nuclear reactor?


  To maintain a steady rate of energy production and prevent overheating.
• What are the applications of nuclear fission?


  • Nuclear power plants for electricity generation
  • Nuclear submarines and ships
  • Medical isotope production
  • Research reactors
  • Nuclear weapons (historical context)
• What is a significant challenge associated with nuclear fission power plants?


  Managing and storing radioactive waste.
• What are the pros of using nuclear fission for power generation compared to fossil fuels?


  It can generate large amounts of electricity and produces less carbon dioxide emissions.
• What is the most significant peaceful application of nuclear fission?


  Nuclear power generation.
• What is the primary function of resistors in a circuit?


  To oppose the flow of electric current
• How do resistors convert electrical energy?


  They convert electrical energy to thermal energy (heat)
• In what unit are resistors measured?


  Ohms (Ω)
• What happens to current flow when resistance increases, assuming voltage remains constant?


  The current decreases
• If a 100Ω resistor allows less current than a 10Ω resistor, what can be inferred about their resistance values?


  The 100Ω resistor has a higher resistance than the 10Ω resistor
• What does Ohm's Law describe?


  The relationship between voltage, current, and resistance
• What is the formula for Ohm's Law?


  $V =$$I \times R$
• If you have a 6V battery connected to a 2Ω resistor, what is the current?


  $I =$$\frac{6}{2} =$$3\, \text{A}$
• What are fixed resistors?


  Components with a constant resistance value
• How do fixed resistors indicate their resistance value?


  Using color-coded bands
• What happens to the current when a 100Ω fixed resistor is replaced with a 200Ω fixed resistor in a circuit with constant voltage?


  The current will be halved
• What are variable resistors also known as?

  Potentiometers or rheostats
• What is a common use for variable resistors?


  Volume control in audio devices
• What happens to the current in a circuit with a fixed voltage source as the resistance of a variable resistor increases?


  The current decreases
• What is the total resistance in a series circuit?


  The sum of individual resistances
• How do series circuits differ from parallel circuits?


  Series circuits have the same current through all components, while parallel circuits have the same voltage across all components
• In a parallel circuit with two identical resistors, how does the current through one resistor compare to the total current?


  The current through one resistor is half the total current
• What are Light Dependent Resistors (LDRs)?


  Components whose resistance changes based on light intensity
• What happens to the resistance of an LDR as light intensity increases?


  The resistance decreases
• In a circuit with a fixed voltage source and an LDR, what happens to the current when light intensity increases?


  The current increases
• What are thermistors?


  Temperature-dependent resistors whose resistance changes with temperature
• What happens to the resistance of an NTC thermistor as temperature increases?


  The resistance decreases