# High Voltage Engineering MCQs Part 11

## Detector circuit used for measuring radio interference voltages

The detector circuit used for measuring radio interference voltages is equipped with a measuring device that is used to measure which of the following values:

1. Quasi-peak value
2. Average value
3. Peak value
4. All of above

Correct answer: 4. All of above

Explanation: The measuring device in the detector circuit for radio interference voltages is designed to measure multiple characteristics of the signal. It can measure the average value, which is the mean value of the voltage waveform over a specific time period. It can also measure the peak value, which represents the highest value reached by the voltage waveform. Additionally, it can measure the quasi-peak value, which is a modified measurement that takes into account the effect of amplitude modulation on interference signals. Therefore, the measuring device is capable of measuring all of these values: average, peak, and quasi-peak.

## In large impulse generators, the spark gaps are usually

In large impulse generators, the spark gaps are usually

1. Sphere gaps
2. Hemispherical gaps
3. Either of these
4. None of these

Correct answer: 3. Either of these

Explanation: In large impulse generators, the spark gaps serve as a means to generate high-voltage impulses. These spark gaps can take the form of either sphere gaps or hemispherical gaps. Both types of gaps have proven to be effective in generating the necessary high-voltage discharges. The choice between sphere gaps and hemispherical gaps may depend on various factors such as the specific design requirements of the generator or the preferences of the manufacturer. Therefore, in large impulse generators, the spark gaps can be either sphere gaps or hemispherical gaps, providing flexibility in their design and implementation.

## Which of below mentioned is an example of artificial fibre is

Which of below mentioned is an example of artificial fibre is

1. Cotton
2. Flax
3. Rayon
4. Silk

Explanation: Artificial fibers are man-made fibers that are created using chemical processes. Rayon is a specific example of an artificial fiber. It is derived from natural cellulose, typically obtained from wood pulp or other plant sources. Rayon is valued for its softness, breathability, and versatility, making it widely used in the textile industry. It is commonly used in the production of clothing, upholstery, and various other textile products. Also see: Meaning of Core number in Electrical cables here

On the other hand, options 1, 2, and 4: cotton, flax, and silk – are examples of natural fibers. Cotton is obtained from the cotton plant, flax is derived from the flax plant, and silk is produced by silkworms. These natural fibers are not considered artificial fibers as they are sourced directly from nature without extensive chemical processing.

## In case of high voltage conductors at high pressures, if voltage is positive, the corona appears as

In case of high voltage conductors at high pressures, if voltage is positive, the corona appears as

1. Reddish glowing spots
2. Uniform bluish white sheath
3. Uniform greenish spots
4. Any of above

Correct answer: 2. Uniform bluish white sheath

Explanation: When high voltage is applied to conductors at high pressures, the phenomenon of corona discharge can occur provided that Critical Disruptive Voltage for Corona Formation is exceeded. Corona discharge is characterized by the ionization of the surrounding air due to the high electric field strength. If the voltage on the conductor is positive, the corona appears as a uniform bluish white sheath surrounding the conductor. This bluish white sheath is the result of the ionization of air molecules, which emit light in the visible spectrum. It is important to note that the appearance of corona can vary depending on factors such as voltage level, conductor shape, and environmental conditions.

## In order to accurately measure ripple voltage in dc systems using CR circuit, the condition to be satisfied is

In order to accurately measure ripple voltage in dc systems using CR circuit, the condition to be satisfied is:

1. ωCR >> 1
2. ωCR << 1
3. ωCR = 1
4. None of above

Correct answer: 1. ωCR >> 1

Explanation: In High Voltage Engineering, one of the simple method of measuring the ripple voltage is by using a capacitance-resistance circuit (CR circuit) and measure the varying component of the AC voltage by blocking the DC component. However in order to measure ripple voltage using this method ωCR >> 1.

Continue reading complete list of High Voltage Engineering Multiple Choice Questions here