Reference no: EM13495382 , Length: 20
1. With the aid of a sketch, explain how compensation is achieved in mercury in steel thermometers.
2. A resistance thermometer has a resistance of 117.254 sl at 18°C. If the temperature coefficient of resistance of the resistance thermometer wire is 0.003664 plot a graph of thermometer resistance to a base of temperature over the range 0°C to 100°C and determine :
(i) the fundamental interval of the thermometer
(ii) the resistance at 65°C.
3. With the aid of a circuit diagram(s) show how a manufacturer can avoid the balancing point of a bridge being affected by the high resistance associated with a dirty slidewire contact.
4. (a) The resistance thermometer bridge circuit shown in FIGURE 1 has a designed maximum temperature of 200°C, ignoring the effects of connecting wire resistance. If the connecting loop is 250 m determine the smallest gauge (swg) of copper wire which must be used if the indicated maximum temperature is to be less than 202°C.
The temperature coefficient of resistance of the thermometer is 0.0042 °C-I and the resistance of the thermometer is 112 C2 at 20°C. Assume the connecting leads are at 20°C.
(b) Using the gauge of copper wire calculated in part (a), calculate the maximum indicated temperature using a 3-wire system (as shown in FIGURE 2) over a distance of 125 m.
5. (a) Explain what is meant by 'the law of intermediate metals' relating to temperature measurement using thermocouples.
(b) With the aid of sketches give two industrial situations to which the law in (a) is applicable.
6. A long length of compensating cable is joined as shown in FIGURE 3. The conductors are not touching directly and the connection is made via the connectors themselves. What effect (if any) will the connection have on the accuracy of the system? Give reasons for your answer.
7. (a) With the aid of a sketch describe the construction and principle of operation of a total radiation pyrometer.
(b) Explain how the following parameters affect the total amount of radiation which is emitted from a hot object :
(i) object temperature
(ii) object surface area.
(c) Explain why the emissivity of a black body is equal to I.
|
Determine the impedance of the series combination
: When a resistor is connected across the terminals of an ac generator (104 V) that has a fixed frequency, there is a current of 0.545 A in the resistor. determine the impedance of the series combination
|
|
How large was the friction torque
: A merry go round has a moment of inertia of 1000 kgm^2. When it is rotating at 2.62 rad/sec, the motor shut off. How large was the friction torque
|
|
What are the basic purposes of antitrust policy
: What are the major components of the current account in the balance of payments? How is the current account balance determined?
|
|
Define a discrete random variable
: Define a discrete random variable
|
|
The law of intermediate metals
: Determine the smallest gauge of copper wire which must be used if the indicated maximum temperature is to be less than 202°C - Explain what is meant by 'the law of intermediate metals' relating to temperature measurement using thermocouples.
|
|
State the total ionic equation and be sure to include
: 1-A 500 mL NaCl solution is diluted to a volume of 1.24 L and a concentration of 8.00 M. What was the initial concentration C1? 2- write the total ionic equation.Be sure to include the charges on the ionic species and the physical state of all the..
|
|
How much was invested at each rate
: 1. The sum of two numbers is 120. If three times the smaller is subtracted from the larger number, the results is 12. Find the two number
|
|
Why might an ecd be preferred to a tcd as a detector
: What methods are used to achieve low levels of corrosion by oxygen in boiler feed water? What measurements are essential to ensure that this is done satisfactorily, and what types of measurement could be used?
|
|
Explain how times faster will the reaction occur
: the activation energy is 18 kj/mol and the overall delta E is -136 kj/mol. How times faster will the reaction occur at 50C than at 0C for the forward reaction
|