Light-Dependent Resistors

• What is the symbol for a light dependent resistor (LDR)?

  It is a specific symbol that represents an LDR in circuit diagrams.
• How does the resistance of an LDR change in light conditions?

  The resistance of an LDR is low in light and high in dark conditions.
• What happens to the resistance of an LDR in dark conditions?

  The resistance of an LDR is high in dark conditions.
• How can LDRs be used in circuits?

  LDRs can be used to detect light and control devices like mobile phone screens.
• What is the relationship between potential difference and current in an ohmic conductor?

  • Current is directly proportional to potential difference.
  • This relationship holds true only if the temperature is constant.
• What is the potential difference across a resistor when the current is measured?

  The current through a resistor is directly proportional to the potential difference.
• What happens to the potential difference across an LDR when it is in light?

  The potential difference across the LDR is low when it is in light.
• What happens to the potential difference across an LDR when it is in darkness?

  The potential difference across the LDR is high when it is in darkness.
• How does an LDR function in a mobile phone?

  • In light, the LDR has low resistance, allowing the screen to light up.
  • In darkness, the LDR has high resistance, dimming or turning off the screen.
• What is the potential difference of the cell in the simplified LDR circuit example?

  The potential difference of the cell is 10 volts.
• How do garden lamps utilize LDRs?

  • The circuit is designed to turn on the light in darkness.
  • The light turns off again in the presence of light.
• What should you be able to do by the end of the video regarding LDRs?

  You should be able to recognize the symbol for an LDR and describe its resistance changes.
• What is the significance of learning the symbol for an LDR?

  It is important for understanding circuit diagrams involving LDRs.