Question 1

The amount of voltage produced by a thermocouple is generally in the order of megavolts.

Accepted Answer

The amount of voltage produced by a thermocouple is generally in the order of millivolts to volts, not megavolts. The amount of voltage produced by a thermocouple is typically in the millivolt range, not megavolt.

Question 2

Thermistors are actually sensitive semiconductor devices.&#10;A)thermally&#10;B)voltage&#10;C)contraction&#10;D)pressure

Accepted Answer

Thermistors are temperature sensitive semiconductor devices that exhibit a large change in resistance with temperature. Thermistors are temperature-sensitive semiconductor devices, meaning their electrical resistance varies with temperature.

Question 3

A bimetal strip is often formed into a spiral.

Accepted Answer

A bimetal strip is often formed into a spiral to enhance its sensitivity to temperature changes. This is true. Bimetal strips are often formed into spirals in order to increase their sensitivity and accuracy when responding to temperature changes.

Question 4

The relay is so named because it uses a length of resistive wire connected in series with the motor to sense motor current.&#10;A)serial thermostat&#10;B)movable arm&#10;C)solid-state starting&#10;D)hot-wire starting

Accepted Answer

The relay described in the question is known as a hot-wire starting relay. It uses a resistive wire, often made of nickel-chromium or tungsten, to sense the current flowing through the motor. As the motor starts, the wire heats up and its resistance increases, which opens the relay and removes the starting capacitor from the circuit.

Question 5

A thermistor with a negative temperature coefficient will exhibit an increase of resistance with an increase in temperature.

Accepted Answer

A thermistor with a negative temperature coefficient will exhibit a decrease in resistance with an increase in temperature. A thermistor with a negative temperature coefficient will exhibit a decrease of resistance with an increase in temperature.

Question 6

The bimetal strip is made by bonding two types of metal together.&#10;A)similar&#10;B)dissimilar&#10;C)related&#10;D)compatible

Accepted Answer

The bimetal strip is made by bonding two dissimilar types of metals together, usually steel and copper or brass. This is done so that when the strip is heated or cooled, the two types of metals expand or contract at different rates, causing the strip to bend or straighten. The bimetal strip is made by bonding two dissimilar types of metal together, usually brass and steel. This creates a strip that will bend when heated due to the difference in thermal expansion between the two metals.

Question 7

One common method of sensing temperature is by the increase of pressure of some chemicals.

Accepted Answer

This is true. One example of such chemicals is a mercury-filled thermometer where the expansion of the mercury due to increased temperature causes an increase in pressure inside the thermometer, which is then read on a calibrated scale. This statement is true. Some chemicals, such as mercury, change in pressure when they experience changes in temperature, allowing them to be used in temperature sensors.

Question 8

Because of the thermistor's ability to change its resistance , they are commonly used as solid&#173;state starting relays.&#10;A)rapidly&#10;B)negatively&#10;C)slowly&#10;D)in calibrated increments

Accepted Answer

Thermistors change their resistance rapidly in response to temperature changes, which makes them suitable for use as solid-state starting relays in various applications.

Question 9

Electrical contacts must never be permitted to open or close slowly.

Accepted Answer

Electrical contacts should open and close quickly to ensure accurate and reliable operation. Slow opening or closing can lead to increased resistance and sparking, which can ultimately result in damage to the contacts and potentially unsafe conditions. Electrical contacts should open and close quickly to prevent arcing and damage to the contacts. Slow opening or closing can cause arcing and lead to electrical issues.

Question 10

Because the voltage of thermocouples is so low, they are often connected in series. This connection is referred to as a ____.&#10;A)type J thermocouple&#10;B)thermistor&#10;C)thermopile&#10;D)serial thermocouple

Accepted Answer

Connecting thermocouples in series allows for an increase in voltage output, which is necessary since the voltage output of a single thermocouple is so low. This arrangement is referred to as a thermopile. Option A is a specific type of thermocouple, option B is a different type of temperature sensor, and option D is not a commonly used term for this arrangement. Connecting thermocouples in series creates a thermopile, which allows for a higher voltage output. Option A is a type of thermocouple, option B is a different type of temperature sensor, and option D is not a commonly used term in this context.

Deck 16: Temperature Switches