Thermistor and Circuit Concepts

This video tutorial covers solving an electricity problem involving a thermistor circuit. It explains the definition of electromotive force and demonstrates how to determine the temperature of a thermistor using resistance and potential difference. The video also discusses the sensitivity range of the thermistor and the effect of temperature changes on the voltage ratio across the circuit components.

What is the definition of electromotive force?

• The voltage drop across a resistor in a circuit.

• The energy supplied by a battery per unit charge.

• The current flowing through a circuit per unit time.

• The resistance offered by a circuit to the flow of current.

In a thermistor circuit, what is the potential difference across the fixed resistor if the total electromotive force is 12 volts and the potential difference across the thermistor is 7.5 volts?

• 4.5 volts

• 12 volts

• 0 volts

• 7.5 volts

How do you calculate the current in a series circuit with a known potential difference and resistance?

• Multiply the potential difference by the resistance.

• Divide the potential difference by the resistance.

• Add the potential difference to the resistance.

• Subtract the resistance from the potential difference.

What is the resistance of a thermistor if the potential difference across it is 7.5 volts and the current is 4.5 x 10^-5 A?

• 100 kilo ohms

• 50 kilo ohms

• 167 kilo ohms

• 200 kilo ohms

According to the graph, what is the temperature when the resistance of the thermistor is 167 kilo ohms?

• -50 degrees Celsius

• 25 degrees Celsius

• 0 degrees Celsius

• -37 degrees Celsius

What is the range of temperature where the thermistor is most sensitive to changes?

• -50 to 0 degrees Celsius

• 0 to 50 degrees Celsius

• -15 to -30 degrees Celsius

• 30 to 50 degrees Celsius

What happens to the resistance of a thermistor as the temperature decreases?

• It becomes zero.

• It remains constant.

• It decreases.

• It increases.

How does a decrease in temperature affect the potential difference across a fixed resistor in a series circuit?

• The potential difference becomes zero.

• The potential difference decreases.

• The potential difference increases.

• The potential difference remains the same.

What is the effect on the current in a circuit when the total resistance increases?

• The current decreases.

• The current becomes zero.

• The current remains the same.

• The current increases.

If the voltage across a thermistor increases while the voltage across a fixed resistor decreases, what happens to the ratio of these voltages?

• The ratio remains constant.

• The ratio decreases.

• The ratio becomes zero.

• The ratio increases.