This is a circuit. Which line in the table shows the changes to the lamp and the voltmeter reading when the temperature rises? Lamp Voltmeter reading gets brighter decreases gets brighter increases gets dimmer decreases gets dimmer increases

Option B is correct. When the temperature of the lamp increases the voltage is also increases, and the lamp brightness is nothing but temperature so that the lamp get brighter.As the temperature rises, the resistance of the thermistor decreases, so the potential difference across it decreases. This is why the voltmeter is across the resistor, not the thermistor.

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What is the use of a thermistor?

Important Questions on Electric Circuits

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

A thermocouple produces a thermo-e.m.f. of

40 μ V / {}^{\circ}C

. A thermopile is made by using

150

such thermocouples. The temperatures of the two junctions are

20 ° C

and

40 ° C

. How much thermo-emf will be generated in the thermopile?

MEDIUM

Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

The resistance of a wire of iron is

10 Ω

and temperature coefficient of resistivity is

5 \times 10^{- 3} ° C^{- 1}

. At

20 ° C,

it carries

30 mA

(milliamperes) of current. Keeping the potential difference between its ends constant, the temperature of the wire is raised to

120 ° C .

The current (in

mA

) that flows in the wire at

120 ° C

is nearly,

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

This is a circuit

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State and explain how the reading on the ammeter changes when the temperature of the thermistor is increased.

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

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The graph in Figure was obtained by measuring the resistance R of a particular thermistor as its temperature e changed. Determine the temperature when its resistance is: $2000 Ω$ .

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

A student connects a circuit with an NTC thermistor, a filament lamp and a battery in series. The lamp glows dimly. The student warms the thermistor with a hair dryer. What change will the student notice in the brightness of the lamp? Explain your answer

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

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The graph in Figure was obtained by measuring the resistance R of a particular thermistor as its temperature e changed Determine the temperature when its resistance is: $5000 Ω$ .

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

Thermistor has a resistance of_____

kΩ

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

The thermistors are usually made of

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

A platinum resistance thermometer reads

0^{o}

when its resistance is

80 Ω

and

100^{o}

when its resistance is

90 Ω

. Find the temperature at the platinum scale at which the resistance is

86 Ω

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

The graph in Figure was obtained by measuring the resistance $R$ of a particular thermistor as its temperature changed.

Determine its resistance at: $20 ° C$

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

A student connects a NTC thermistor to a battery and an ammeter. He places the thermistor in a beaker of water and gradually heats the water from 10 oc to its boiling point, recording the value of the current as he does so. He then plots a graph of the current in the thermistor against the temperature of the water Explain how the student could now use the thermistor as a thermometer.

Question Image

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

The resistance of a metal wire changes with temperature. This means that a wire could be used to sense changes in temperature, in the same way that a thermistor is used

Suggest one advantage a thermistor has over a metal wire for this purpose.

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

a) Draw the circuit symbol for a thermistor.

b) Give one use for a thermistor.

c) Explain why a thermistor is suitable for this use.

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

This is a circuit.

Question Image

Which line in the table shows the changes to the lamp and the voltmeter reading when the temperature rises?

Lamp	Voltmeter reading
gets brighter	decreases
gets brighter	increases
gets dimmer	decreases
gets dimmer	increases

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

The resistance of a bulb filament is

100 Ω

at a temperature of

100 ° C

. If its temperature coefficient of resistance is

0.005

° C^{- 1}

, its resistance will become

200 Ω

at a temperature of,

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

A student connects a thermistor to a battery and an ammeter. He places the thermistor in a beaker of water and gradually heats the water from $10 ° C$ to its boiling point, recording the value of the current as he does so. He then plots a graph of the current in the thermistor against the temperature of the water

(a) Sketch the graph you would expect the student to obtain from the experiment

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

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The graph in Figure was obtained by measuring the resistance R of a particular thermistor as its temperature e changed. Determine its resistance at: $45 ° C$ .

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

Cotyledons are also called-

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Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

Two resistances,

R_{1}

and

R_{2}

are made of different materials. The temperature coefficient of the material of

R_{1}

α

and of the material

R_{2}

- β .

The resistance of the series combination of

R_{1}

and

R_{2}

will not change with temperature if

\frac{R_{1}}{R_{2}}

equals,

MEDIUM

Physics>Electricity and Magnetism>Electric Circuits>Electric Circuits

A resistance thermometer reads

R = 20.0 Ω

27.5 Ω

, and

50.0 Ω

at the ice point

(0^{o} C)

, the steam point

(100^{o} C)

and the zinc point

(420^{o} C)

respectively. Assuming that the resistance varies with temperature as

R_{θ} = R_{0} (1 + αθ + {βθ}^{2})

, find the values of

R_{0}

α

and

β

. Here

θ

represents the temperature on Celsius scale.

What is the use of a thermistor?

Important Questions on Electric Circuits

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