All of the following are the preferred properties of a dielectric gas EXCEPT
1.high dielectric strength
2.physiological inertness
3.low atomic number
4.good heat transfer
Posted Date:-2022-04-08 09:32:46
Candela is-the unit for
1.Light flux
2.Luminous intensity
3.Brightness
4.Luminous efficiency
Posted Date:-2022-04-08 10:25:12
Electro-mechanical breakdown of solid insulating materials occurs due to
1.magnetic bum
2.vibrations
3. mechanical stresses produced by the electrical field
4.electrical stresses produced by the voltage fluctuations
Posted Date:-2022-04-08 09:34:40
Impulse testing of transformers is done to determine the ability of
1.bushings to withstand vibration
2. insulation to withstand transient voltages
3.windings to withstand voltage fluctuations
4.all of the above
Posted Date:-2022-04-08 09:45:14
Insulators for high voltage applications are tested for
1.power frequency tests
2.impulse tests
3.both (A) and (B) above
4.None of the above
Posted Date:-2022-04-08 09:46:11
Melting temperature of tungsten is
1. 2000°K
2.2500°K
3. 2655°K
4.3655°K
Posted Date:-2022-04-08 10:14:02
Switching surge is
1.high voltage dc
2.high voltage ac
3.short duration transient voltage
4.hyperbolically dying voltage
Posted Date:-2022-04-08 09:48:01
The electrical breakdown strength of insulating materials depends on
1.nature of applied voltage
2.imperfections in dielectric material
3.pressure, temperature and humidity
4.all of the above
Posted Date:-2022-04-08 09:42:54
Which bulb operates on lowest power ?
1.Night bulb
2.Neon bulb
3.GLS bulb
4.Torch bulb
Posted Date:-2022-04-08 10:23:07
A zero watt lamp consumes A.
1.no power
2.about 5 to 7 W power
3.about 15 to W power
4. about 25 to 30 W power
Posted Date:-2022-04-08 10:15:38
Corona results in
1. improvement in power factor
2.increased capacitive reactance of transmission lines
3.radio interference
4.better regulation
Posted Date:-2022-04-08 06:38:17
Light is produced in electric discharge lamps by
1.heating effect of current
2.magnetic effect of current
3.ionization in a gas or vapor
4.carbon electrodes
Posted Date:-2022-04-08 10:26:51
Liquids are generally used as insulating materials up to voltage stresses of about
1.100 MV/cm
2. 50 MV/cm
3. 50 KV/cm
4. 500 V/cm
Posted Date:-2022-04-08 09:36:13
Lumen/watt is the unit of
1.Light flux
2.Luminous intensity
3.Brightness
4. Luminous efficiency
Posted Date:-2022-04-08 10:25:59
Moles bridge is used to measure
1. properties of dielectric at dc
2.dispersion in insulation
3.high frequency high voltages
4.modulation ratio frequencies
Posted Date:-2022-04-08 09:47:17
Surge voltage originate in power systems due to
1.lightning
2.switching operations
3.faults
4.any of the above
Posted Date:-2022-04-08 09:33:44
The color temperature of day light is around
1.50 K
2.160 K
3.600 K
4.6000 K
Posted Date:-2022-04-08 10:27:40
The output of a tungsten filament lamp depends on
1.size of lamp
2. size of shell
3. temperature of filament
4.All of the above
Posted Date:-2022-04-08 10:16:47
Vacuum insulation is used in all of the following EXCEPT
1.Particle accelerators
2.EHT of color TV
3.EHT of color TV
4.X-rays
Posted Date:-2022-04-08 09:38:39
Which gas is sometimes used in filament lamps ?
1.Argon
2. Krypton
3.Nitrogen
4.Carbon dioxide
Posted Date:-2022-04-08 10:24:04
Which of the following gas has been used as insulating medium in electrical appliances ?
1.Nitrogen
2.Carbon dioxide
3.Sulphur hexafluoride
4.Freon
Posted Date:-2022-04-08 09:41:10
Which photometer depends for its operation on Inverse Square Law ?
1. Guilds Flicker Photometer
2.Lummer Brodhum Photometer
3.Macbeth llluminometer
4. Trotter Illumination Photometer
Posted Date:-2022-04-08 10:28:31
Which photometer depends for its operation on Inverse Square Law ?
1. Guilds Flicker Photometer
2.Lummer Brodhum Photometer
3.Macbeth llluminometer
4. Trotter Illumination Photometer
Posted Date:-2022-04-08 10:32:14