What is phosphorescence and fluorescence?

What is phosphorescence and fluorescence?
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1 Answer

Answer :

Fluorescence is the light produced when the source of energy is applied. The light produced after the removal of source of energy is known as phosphorescence.
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Related questions

What can emit an umbra on the earth, provide phosphorescence for all it's creatures. All while altering the visual surface of itself within phases? -Riddles

Description : What can emit an umbra on the earth, provide phosphorescence for all it's creatures. All while altering the visual surface of itself within phases? -Riddles

Last Answer : The moon.

Which of the following statement(s) is/are correct? (1) Persistence is the term used to describe the duration of phosphorescence. (2) The control electrode is used to turn the electron beam on and off. (3) The electron gun creates a source of electrons which are focussed into a narrow beam directed at the face of CRT. (4) All of the above.

Description : Which of the following statement(s) is/are correct? (1) Persistence is the term used to describe the duration of phosphorescence. (2) The control electrode is used to turn the electron beam on and off. (3) ... which are focussed into a narrow beam directed at the face of CRT. (4) All of the above. 

Last Answer : All of the above.

What is fluorescence ?

Description : What is fluorescence ?

Last Answer : : Substances that absorb the 200-375 nanometer wavelength spectrum of the UV region but emit visible spectra with a wavelength of 400-780 nanometers are called fluorescence substances.

The fluorescence of the glass (discharge) tube at very low pressure is characteristic of_________.

Description : The fluorescence of the glass (discharge) tube at very low pressure is characteristic of_________.

Last Answer : The fluorescence of the glass (discharge) tube at very low pressure is characteristic of_________. A. ... tube C. the cathode D. the emitted particles

What is immuno fluorescence ?

Description : What is immuno fluorescence ?

Last Answer : Fluorescence is the property of absorbing light ray of particular wavelength and emitting rays in different wavelength. Antigens that are bound to cells or tissue sections can be visualized by tugging the antibody molecule with a fluorescent dye or fluorochrome.

Into how many types is immuno fluorescence is divided ?

Description : Into how many types is immuno fluorescence is divided ?

Last Answer : Immuno fluorescence is divided into 2 types- Direct immuno fluorescence Indirect immuno fluorescence

What is direct immuno fluorescence ?

Description : What is direct immuno fluorescence ?

Last Answer : In this method, the species antibodies are primary antibodies, which are directly conjugated to fluorescent dye.

What is the disadvantage of direct immuno fluorescence ?

Description : What is the disadvantage of direct immuno fluorescence ?

Last Answer : A separate fluorescent conjugate have to be prepared against each antigen to be tested.

What is indirect immuno fluorescence ?

Description : What is indirect immuno fluorescence ?

Last Answer : In a method the primary unlabelled antibody is detected with a number of reagents have been developed for indirect staining. The most common is fluorescence labeled anti isotype antibody such as fluoroscin labeled goat- mouse antibody.

What are the advantages of indirect immuno fluorescence ?

Description : What are the advantages of indirect immuno fluorescence ?

Last Answer : The primary does not need to be conjugated with label. It increases the sensitivity of staining because multiple fluorochrome reagents will bind to each antibody molecule. This method has great flexibility.

What are the uses of indirect immuno fluorescence ?

Description : What are the uses of indirect immuno fluorescence ?

Last Answer : For identifying bacterial species Detecting antigen-antibody complexes in autoimmune diseases Detecting compliment components in tissues. Localizing hormones

When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy state, they emit light, which we can observe in - (1) Raman spectra (2) Absorption spectra (3) Emission spectra (4) Fluorescence

Description : When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy state, they emit light, which we can observe in - (1) Raman spectra (2) Absorption spectra (3) Emission spectra (4) Fluorescence

Last Answer : (3) Emission spectra Explanation: When a metal atom is strongly heated, its electrons absorb the heat energy and jump to a higher energy level. When the electron returns to its original position it ... to the energy the electron has released at each stage °fits fall back to its original state.

Pick out the wrong statement. (A) A pale color of petroleum product indicates lower viscosity (B) Color of petroleum products indicates the degree of refinement (C) Lighter petroleum distillates are lighter in color than the heavier residual oils (D) Fluorescence of oils helps to detect its adulteration

Description : Pick out the wrong statement. (A) A pale color of petroleum product indicates lower viscosity (B) Color of petroleum products indicates the degree of refinement (C) Lighter petroleum distillates are ... in color than the heavier residual oils (D) Fluorescence of oils helps to detect its adulteration

Last Answer : (A) A pale color of petroleum product indicates lower viscosity

Particle nature of cathode rays is proved due to the fact that they (A) Travel in a straight line (B) Get deflected by magnetic electric field (C) Produce fluorescence (D) Heat the exposed material

Description : Particle nature of cathode rays is proved due to the fact that they (A) Travel in a straight line (B) Get deflected by magnetic electric field (C) Produce fluorescence (D) Heat the exposed material

Last Answer : Option B

In organic molecules, fluorescence seldom results from absorption of UV radiation of wavelengths lower than (A) 350 nm (B) 200 nm (C) 300 nm (D) 250 nm

Description : In organic molecules, fluorescence seldom results from absorption of UV radiation of wavelengths lower than (A) 350 nm (B) 200 nm (C) 300 nm (D) 250 nm

Last Answer : (A) 350 nm

Indicate the HPLC detector that is most sensitive to change in temperature : (A) PDA detector (B) Refractive Index detector (C) Electrochemical detector (D) Fluorescence detector

Description : Indicate the HPLC detector that is most sensitive to change in temperature : (A) PDA detector (B) Refractive Index detector (C) Electrochemical detector (D) Fluorescence detector

Last Answer : (B) Refractive Index detector

Which one of the following statements is WRONG? (A) A singlet or triplet state may result when one of the electrons from the HOMO is excited to higher energy levels (B) In an excited singlet state, the spin of the electron in the higher energy orbital is paired with the electron in the ground state orbital (C) Triplet excited state is more stable than the singlet excited state (D) When the electron from the singlet excited state returns to ground state, the molecule always shows fluorescence phenomenon

Description : Which one of the following statements is WRONG? (A) A singlet or triplet state may result when one of the electrons from the HOMO is excited to higher energy levels (B) In an ... the electron from the singlet excited state returns to ground state, the molecule always shows fluorescence phenomenon

Last Answer : (C) Triplet excited state is more stable than the singlet excited state

Which of the following HPLC detectors is used as a bulk property or general purpose detector? A. Electrochemical detector B. Fluorescence detector C. UV-Visible detector D. Evaporative Light scattering detector

Description : Which of the following HPLC detectors is used as a bulk property or general purpose detector? A. Electrochemical detector B. Fluorescence detector C. UV-Visible detector D. Evaporative Light scattering detector

Last Answer : D. Evaporative Light scattering detector

Hydraulic lime is not used in plastering because it may result in a) Blistering* b) Efflorescence c) Flaking d) Fluorescence

Description : Hydraulic lime is not used in plastering because it may result in a) Blistering* b) Efflorescence c) Flaking d) Fluorescence

Last Answer : a) Blistering*

The fluorescence examination of the seminal stains indicates (a). Pink color (b). White color (c). Blue color (d). Red color

Description : The fluorescence examination of the seminal stains indicates (a). Pink color (b). White color (c). Blue color (d). Red color

Last Answer : Ans: (b). Blue color 

Which of the following is an example of bulk property or general detector in HPLC A. Fluorescence detector B. Refractive index detector C. Electrochemical detector D. UV-Visible detector

Description : Which of the following is an example of bulk property or general detector in HPLC A. Fluorescence detector B. Refractive index detector C. Electrochemical detector D. UV-Visible detector

Last Answer : Refractive index detector

When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy siate, they emit light, which we can observe in (1) Raman spectra (2) Absorption spectra (3) Emission spectra (4) Fluorescence

Description : When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy siate, they emit light, which we can observe in (1) Raman spectra (2) Absorption spectra (3) Emission spectra (4) Fluorescence

Last Answer : Emission spectra

need of calibration and explain the procedure to calibrate the instrument.

Description : need of calibration and explain the procedure to calibrate the instrument.

Last Answer : Need of calibration: Every measuring device degrades over time due to normal wear and tear. These changes can be caused by various reasons such as electric or mechanical shock or a hazardous manufacturing ... different magnitude are used to calculate the resistance based on ohm's law.

Compare Dual slope DVM and SAR type DVM.

Description : Compare Dual slope DVM and SAR type DVM.

Last Answer : Sr no Dual slope DVM SAR type DVM 1 It is highly accurate It is moderately accurate 2 Cost is high It is inexpensive 3 Two comparator is used One comparator is used ... resolution Good resolution 5 Slow speed High speed 6 Less Error More error

block diagram of logic analyzer.

Description : block diagram of logic analyzer.

Last Answer : A logic analyzer can be triggered on a complicated sequence of digital events, then capture a large amount of digital data from the system under test (SUT).When logic analysers first came ... Once the data are captured, they can be displayed several ways, from the simple) to the complex 

operation of DSO with block diagram.

Description : operation of DSO with block diagram.

Last Answer : The input is amplified and attenuated with input amplifiers. The output of the input signal amplifiers feeds an analog to digital converter (ADC). There are numbers of ADC available. But the selection of ADC ... view the display on the CRT, the data from memory is reconstructed in analog form.

sketch time period measurement by CRO.

Description : sketch time period measurement by CRO.

Last Answer : Horizontal sweep is turned ON and the display appealing on the screen is adjusted by varying different control knobs provided on the front panel of CRO, till the signal is suitably displayed ... Where m=Number of division in one complete cycle n=Setting of time base =Time/Division

operation of ramp type DVM.

Description : operation of ramp type DVM.

Last Answer : This is given to an input comparator which will compare two signals and generates the output. One input to the input comparator is from the input and another input is from the ramp. This input voltage and ... ground and output is given. This output will stop the flow of purchase from clock

operation of half wave rectifier type AC Voltmeter.

Description : operation of half wave rectifier type AC Voltmeter.

Last Answer :  Half-wave Rectifier Voltmeter The d'Arsonval meter movement only responds to the average or dc value of the current through the moving coil. In order to measure alternating ... ) input voltage signal alternating signal needs to be rectified first by using diode rectifier to produce 

operation of whetstone bridge.

Description :  operation of whetstone bridge. 

Last Answer : A Wheatstone bridge is widely used to measure the electrical resistance. This circuit is built with two known resistors, one unknown resistor and one variable resistor connected in the form of bridge. ... using a Wheatstone Bridge the unknown electrical resistance value can easily measure.

role of the series resistance connected in PMMC movement.

Description : role of the series resistance connected in PMMC movement.

Last Answer : A PMMC Instrument can be used as voltmeter by just connecting a series resistance with the moving coil. This series resistance is called Voltmeter Multiplier. This combination of moving coil and ... current whose voltage is to be measured. Ideally the resistance of voltmeter should be infinite

different types of errors occurs in measurement.

Description : different types of errors occurs in measurement.

Last Answer : Generally errors are classified into three types: systematic errors, random errors and blunders. 1) Gross Errors 2) Random Errors 3) Systematic Errors Instrumental Errors Environmental ... to wrong observations or reading in the instruments particularly in case of energy meter reading. 

tern null as it applies to bridge measurement.

Description : tern null as it applies to bridge measurement.

Last Answer : Null measurements balance voltages so that there is no current flowing through the measuring device and, therefore, no alteration of the circuit being measured. Null measurements are generally more ... the use of standard voltmeters and ammeters, and they still have limits to their precision.

application of CRO.

Description : application of CRO.

Last Answer : Applications of CRO: 1) Voltage measurement. 2) Current measurement. 3) Measurement of phase difference. 4) Measurement of phase. 5) Measurement of frequency. 6) Measurement of inductance. ... in various circuits. 17) For checking transistor. 18) It can measure short time interval.

How many non-overlapping channels are available in IEEE 802.11b

Description : How many non-overlapping channels are available in IEEE 802.11b

Last Answer : 3 non-overlapping channels are available in IEEE 802.11b

Number of comparators required for an 8 bit flash ADC is:

Description : Number of comparators required for an 8 bit flash ADC is: (1) 8 (2) 16 (3) 255 (4) 256

Last Answer : Number of comparators required for an 8 bit flash ADC is: 255

In D/A converter, the resolution required is 50mv and the total maximum input is 10v. The number of

Description : In D/A converter, the resolution required is 50mv and the total maximum input is 10v. The number of bits required is   (A) 7 (B) 8 (C) 9 (D) 200

Last Answer : In D/A converter, the resolution required is 50mv and the total maximum input is 10v. The number of  bits required is 8 

Choose the correct statement (a) Digital multimeters are built using current measuring elements, while analog

Description : Choose the correct statement  (a) Digital multimeters are built using current measuring elements, while analog multimeters are built using voltage measuring units (b) Digital multimeters are built ... measuring units (d) Both digital and analog multimeters are built using current measuring units

Last Answer : Choose the correct statement  (a) Digital multimeters are built using current measuring elements, while analog multimeters are built using voltage measuring units (b) Digital multimeters are built ... measuring units (d) Both digital and analog multimeters are built using current measuring units

An analog voltmeter has a sensitivity of 10kΩ/volt. The galvanometer used in constructing the instrument

Description : An analog voltmeter has a sensitivity of 10kΩ/volt. The galvanometer used in constructing the instrument will produce a full scale deflection when the current passed through it is  (a) 10 mA (b) 20 mA (c) 50 mA (d) 100 μA

Last Answer : An analog voltmeter has a sensitivity of 10kΩ/volt. The galvanometer used in constructing the instrument will produce a full scale deflection when the current passed through it is 100 μA

An optical fiber cable laid underground has developed a discontinuity at a distance d from the source end.

Description : An optical fiber cable laid underground has developed a discontinuity at a distance d from the source end. The fault can be located using the instrument  (a) Optical spectrum Analyzer (OSA) (b) Optical Time Domain Reflectometer (OTDR) (c) Optical Power Meter (OPM) (d) Laser Diffractometer (LD)

Last Answer : An optical fiber cable laid underground has developed a discontinuity at a distance d from the source end. The fault can be located using the instrument Optical Time Domain Reflectometer (OTDR) 

Two sinusoidal signals of the same frequency are displayed on a dual-trace oscilloscope. One complete cycle

Description : Two sinusoidal signals of the same frequency are displayed on a dual-trace oscilloscope. One complete cycle of each signal covers 6 cm of the horizontal scale and the starting point of the horizontal scale and the starting ... between the two signals in degrees is  (a) 30 (b) 45 (c) 60 (d) 90

Last Answer : Two sinusoidal signals of the same frequency are displayed on a dual-trace oscilloscope. One complete cycle of each signal covers 6 cm of the horizontal scale and the starting point of the horizontal ... signals are separated by 0.5 cm. The phase difference between the two signals in degrees is 30

Transient signals can be observed using

Description : Transient signals can be observed using  (a) storage oscilloscope (b) sampling oscilloscope (c) wave analyzer (d) spectrum analyzer

Last Answer : Transient signals can be observed using storage oscilloscope

The trace on an oscilloscope continually moves to the right of the screen when

Description : The trace on an oscilloscope continually moves to the right of the screen when  (a) the sweep is triggered. (b) the sweep period is larger than the signal period. (c) the sweep period is smaller than the signal period. (d) there is no weep.

Last Answer : The trace on an oscilloscope continually moves to the right of the screen when the sweep period is smaller than the signal period. 

In a dual trace oscilloscope, the display appears segmented when

Description : In a dual trace oscilloscope, the display appears segmented when  (a) low frequency signals are observed in Alternate mode (b) low frequency signals are observed in Chop mode (c) high frequency signals are observed in Alternate mode (d) high frequency signals are observed in Chop mode

Last Answer : In a dual trace oscilloscope, the display appears segmented when high frequency signals are observed in Chop mode

To distinguish between signals having very close values, we need an instrument with

Description : To distinguish between signals having very close values, we need an instrument with  (a) high accuracy (b) high resolution (c) high sensitivity (d) high linearity

Last Answer : To distinguish between signals having very close values, we need an instrument with high resolution

In a weighted-resistor digital-to-analog converter with 8-bit input, if the resistance corresponding to the MSB

Description : In a weighted-resistor digital-to-analog converter with 8-bit input, if the resistance corresponding to the MSB is 2K, what will be the resistance corresponding to the LSB?  (a) 250 Ω (d) 512 KΩ (c) 256 KΩ (d) 25.5 Ω

Last Answer : In a weighted-resistor digital-to-analog converter with 8-bit input, if the resistance corresponding to the MSB is 2K, what will be the resistance corresponding to the LSB?  (a) 250 Ω (d) 512 KΩ (c) 256 KΩ (d) 25.5 Ω

ESD stands for

Description : ESD stands for

Last Answer : ESD stands for Electro static Discharge

In a particular circuit connection, AWG 18 wire is selected over AWG 22. The reason is that it is having

Description : In a particular circuit connection, AWG 18 wire is selected over AWG 22. The reason is that it is having

Last Answer : In a particular circuit connection, AWG 18 wire is selected over AWG 22. The reason is that it is having Higher current carrying capacity

Very small displacements are effectively measured using

Description : Very small displacements are effectively measured using

Last Answer : Very small displacements are effectively measured using LVDT

Y –axis in a CRO normally represents

Description : Y –axis in a CRO normally represents

Last Answer : Volt