The unit mcd, or millicandela, is a standard unit for measuring the intensity of a light source. Correct explanation : Luminous intensity typically is represented by the symbol I ν, where the subscript ν denotes a photometric quantity, and its unit is the candela, an SI base unit (1 cd = 1 lumen/steradian, where the … The LS126C UV light intensity meter also has an intelligent statistical function, which displays real-time value, maximum value, minimum value, average value, measurement duration, date and time. Therefore, all fluorescent penetrants and magnetic particle materials are tuned to fluoresce under UV-A at 365 nm. Answer: Atomic clocks are used in Global Positioning System (GPS), Global Navigation Satellite System (GLONASS) and International time distribution services. The radiation intensity of UV lamps can be monitored by UV light meter and the data can be used to analyze whether the UV lamps are attenuated. (c) Temperature So if your bulb was 10cm long with a 15 W power, you'd expect an SR of 15W/0.1 = 150 W/m. … How much UV-light exposure time is required to disinfect a laminar flow hood? But I suppose any book dealing with radiation could help as inverse square distance law is a general law. Answer: True, Question 6. Question 2. Question 2. Solution: (b) Integrated System of units quick buy. There are two 6W UV bulbs inside BG-12-AA which makes it a total 12W lamp. Question 4. Answer: In literature, I have found out an example in which they use a 370 nm wavelength with a power of 30 mW/cm2 for 3 minutes. Radiant Intensity is a measure of radiometric power per unit solid angle, expressed in watts per steradian. Originated from the term candles, candela refers to luminous intensity; how strong is the light to a naked eye; The higher the luminous intensity, the higher the sensitivity it is to our eyes; Lumen. Normal temperature of the human body is between 98.4° F and 98.6° F. Question 7. it's typically used for post-curing of 3D printed parts, so perhaps too powerful. [3.4] (of a point source of light in a given direction) I = dPhi /domega . Answer: Answer: Correct statement: The two types of photoluminescence familiar to most of us are fluorescence and phosphorescence. Difference between Plane Angle and Solid Angle: From your data you can calculate the radiant intensity for the specific direction and then recalculate for the necessary distance. time. The number of lumens per square meter is called lux . Seven. Round off the number 5.323 to two decimal places. When i check for Uv-C lamp providers their data is given in UV output ( in Watts ) but for selection of suitable lamp, i will need data of UV Irradiance ( watts sec / cm2) . Answer: Which one the following system of units is the British System of unit? It is in the case of  UV tube that emits UV light at 254 nm, (mercury line) having strong germicidal activity. Assertion : The seconds hand of a clock is having least count of one second. Answer: Assertion : Temperature is a physical quantity. Question 1. The measure of the power of the emitted light, by a light source in a particular direction, per unit solid angle is called as luminous intensity. Answer: STER-L-RAY ® High Intensity germicidal uv lamps are manufactured with a unique structure and large diameter quartz envelope which translates to more … (b) A number and a unit The SI unit of mass is …………….. Hours Hand : It is short and thick. (b) If both assertion and reason are true, but the reason is not the correct explanation of the assertion. The distance from the source of my sample (in the configuration that we have designed in our lab) is equal to 3 cm. Step : 1 Identify the last digit to be kept. Luminous Intensity is the amount of visible light, that is emitted in unit area per unit ……………. (c) Directly proportional to the square of number of atoms (a) Both assertion and reason are true and the reason is the correct explanation of the assertion. Question 5. 6.023 x 1023. These clocks have an accuracy of one second in every 10b seconds. How can I measure its intensity in terms of wavelength? It makes one rotation in one minute and 60 rotations in one hour. The measured peak light intensity is shown as a function of dose rate in Fig. Reason : Least count is the maximum measurement that can be measured accurately by an instrument. Answer: (a) International system of units, Question 8. As both 6W bulbs light up together when switched on. This means the more strongly a light source is heated up, the higher its luminous intensity will be. The value of every measurement contains some uncertainty. Analog clock and digital clock. Med. Define – ampere. (c) A number The super conductors are used to levitate trains from the track. What are the differences between Plane angle and solid angle? (b) Precision, Question 9. LED Luminous intensity. Thermometer. The frequency of a vibrating crystal is very precise. Mention its SI unit and symbol. > What is the difference between the luminous intensity and brightness of light (and all other types of electromagnetic radiations)? (c) Approximation is very useful when little information is available. UV A light source (365nm, 8 watts) Aimed at a surface 5 cm away for 7 Days, UV B light source (302nm, 8 watts)Aimed at a surface 5 cm away for 7 Days, UV C light source (254nm, 8 watts)Aimed at a surface 5 cm away for 7 Days. (d) Energy quantities How to control the radiation dose? Answer: (a) International system of units Ammeter is a device used to measure electric current. (d) IR light I plan to use a UV lamp to create DNA breaks in the cells. Luminous intensity is the intensity of All rights reserved. (d) Inversely proportional to the square of number of atoms (c) kelvin, Question 4. The unit of mass in CGS system is kilogram. (b) Derived quantities (d) If the assertion is false, but the reason is true. The JLT800 UV meter simplifies measurement by continuously sampling until UV light is detected, then automatically measuring. Reason : Temperature is the degree of hotness or coldness of a body. Answer: The intensity of the light would double to 20 candelas, but the solid angle would halve to 2π steradians. is a physical quantity that expresses the degree of hotness or coldness of a substance. Answer: Luminous intensity … (a) Both assertion and reason are true and reason is the correct explanation of the assertion. Reason : Avogadro’s number is a constant. What is the unit of mass in FPS system? How to Measure Light Intensity Using a Light Meter. (d) Ampere Question 8. Base Quantities and Units: Question 2. Answer: Only for input power between approximately zero and 0.08 W is the input power linearly related to the square of light intensity. Melting point of pure ice (0° C) is taken as ……………… fixed point. Question 4. 57 (2012) 6661–6670. In TUNGSRAM Innovation is our Heritage The visual sensation of the luminous intensity of a light source. Quantities other than base quantities are called as True, Question 7. (a) Approximation gives accurate value. Temperature is a physical quantity that expresses the degree of hotness or coldness of a substance. Question 6. Answer: Amount of heat and UV radiation emitted. Convert 100 K into Celsius. 2. What is the SI unit of Luminous Intensity? Your email address will not be published. Answer: LEDs emit almost no forward heat while traditional bulbs like incandescents convert more than 90% of the total energy used to power them directly into heat. Write any 2 applications of various thermometric scales. These uncertainties are called as ‘Errors’. Equally, cylinder models aren't great as the orientation UV radiation is received at matters. Question 2. One coulomb of charge flowing per minute is called ‘ampere’. Mention its SI unit and symbol. I am currently working on UV sanitation system. How many base quantities are there? The magnitude of a physical quantity consists of …………….. (a) Celsius (c) Visible light Intensity … Given that a UV bulb with 2x15 Watt, wavelength of 365nm, the intensity at 15cm is 2300uW/cm2. Define one light year. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when the Sun is above the horizon.When direct solar radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright light … (b) Supplementary Question 5. Question 4. Radian is the unit of plane angle. (b) Both assertion and reason are true, but the reason is not the correct explanation of the assertion, Question 2. Quartz clocks are used in GPS Devices. The UV lamp in our lab is fixed in the cell culture hood (Ushio germicidal bulb, UVC, wavelength 253.7 nm, 15 watt, 55 volt) and I need to introduce 5J/m2 to my cells. Just wondering how we calculate the intensity. Write its formula and unit. Production UV-LED sources have their spectral emissions somewhere in the 365 to 405-plus nm region. Answer: (c) Assertion is true, but reason is false (c) FPS, Question 5. Emits far energy at 10,600 nm (10.6 µm). Assertion : Electric current, amount of substance, Luminous Intensity are the fundamental physical quantities. What is measurement? Answer: (d) kilometre The difference between the real value and the observed value is called an error. Measurement is the base of all experiments in science and technology. Answer: ……………… is the closeness of the measured value to the original value. Types of clocks based on display: 1. How can I calculate the UV dose, in J/m2? It is also important to know the dimensions of the lamp as well as the radiation pattern (radiant intensity distribution). The SI unit of length is the ………………. (d) SI (b) Both assertion and reason are true but reason is not the correct explanation of the assertion Energy consumption. A digital clock displays the time directly. Answer: Question 7. Electric current = $$\frac { Amount of electric charges (Q) }{ time (t) }$$ There isn’t a formal definition of brightness, but to most people it means how strong a light … True or False – if false give the correct statement. (b) Fahrenheit Control gear must include end-of-life protection (IEC60662, IEC 62035) It is an estimation of a number obtained by rounding off a number to its nearest place value. Please mention the source of UV-B. Direction: Mark the correct choice as. (a) Accuracy Joahnna, is 15W the electrical power of the lamp or optical? (d) Assertion is false, but reason is true] (c) Metre, Question 2. Question 7. It shows ‘minute’. Answer: Answer: When the formulas for penetrants and magnetic particle materials were created, the default UV-A source was mercury-vapor, which produce a single UV-A peak at 365.4 nm, the elemental emission line of mercury. Answer: Question 3. The SR quantity in the answer I gave above is in fact the linear power density of the source, with units of W/m. These clocks are activated by ‘electronic oscillations’, which are controlled by a ‘quartz crystal’. Answer: UV-LEDs are described and … Question 1. (a) Both assertion and reason are true and the reason is the correct explanation of the assertion, Question 3. This is my goal. (a) directly proportional to the number of atoms, Question 5. Correct statement: Correct statement: Question 8. Light intensity … ……………… is the process of finding an unknown physical quantity by using a standard quantity. Answer: Answer: Question 3. But do I have mercury line here? (c) Derived The measure of the power of the emitted light, by a light source in a particular direction, per unit solid angle is called as luminous intensity. Answer: Biol. Normal temperature of the human body is between 98.4° C and 98.6° C. VI. How can i calculate the UV Irradiance from UV output ( watts) ? Correct statement: Question 1. rouge coco flash colour, shine, intensity in a flash £31.00. Question 6. Answer: (b) Inversely proportional to the number of atoms (d) SI For … The Luminous Flux from a monochromatic source producing light at a single wavelength is easiest to determine. Answer: (d) kilogram luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye.The SI unit of luminous intensity is the candela (cd), an SI base unit.. Photometry deals with the measurement of visible light … Define – Temperature. (c) FPS These regions are called as ‘Time Zones’. Actually the point is: does the bigger distance (19 cm vs 0.5 cm) compensate the higher energies (250 mW/cm2 vs 6 mW/cm2)? (b) Luminous intensity False Explain the Greenwich mean time. Answer: Least count is the minimum measurement that can be measured accurately by an instrument. What is the ‘Lower Fixed Point’ of the Fahrenheit scale? Answer: Hi, my question is: if we know that the intensity at 15 cm is 350 µW/cm2, how we can calculate the intensity of the same bulb at a distance of 3 cm? (c) Metre Answer: Answer: Closeness of two or more measured values is called as Candela is used to express electric field intensity. The brightness of a laser beam is most closely associated with the radio-metric concept of radiance. As Watt= Joule/sec, it seems that to have 5J/m2 from a 15W bulb I just need to consider the time I expose my cells in UV(sec) and the m, Is that way of calculation appropriate? But if the source has a reasonable extent, then this is not an adequate assumption; typically, to use a point source approximation you must be at least 5x as far from your source as the greatest extent of your source for the simplification to hold. UV free Light Therapy Lamp: Miroco Light Therapy Lamp has an intensity of 10,000 lux in a pure white color 6500K that’s designed to imitate the daylight at noon. C = K – 273 Assertion : The SI unit of temperature is kelvin. I want to use it for microbial inactivation. In general inverse square distnace law is the solution for simplified calculations. You can Download Samacheer Kalvi 8th Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations. K = C + 273 (a) Electric current Given: i = $$\frac { π }{ 180° }$$. Answer: (b) UV light A (ampere). Tell me more about spectra. (d) Approximation gives the nearest value only. (v) 100, Question 1. (b) Gram Amount of substance is 1 minute = $$\frac { 1 }{ 60 }$$ = 0.0167 hours. Precision : Precision is the closeness of two or more measurements to each other. Luminous intensity is the power (adjusted for human eye perception called the luminosity function) of light in a unit solid angle. VII. Question 5. Curve display is used to analyze the change trend of the luminous intensity … Angle between the intersection of three or more planes at a common point. True. Answer: Closed Installation Contents: - Effect of Ultraviolet - UV-C Production - Ultraviolet Dose - Dose/Destruction Relationship - Applications - Medium and High Pressure Arc Tubes - Low Pressure Lamps - Irradiation Chambers - Single Arc Tube Configuration - UV Intensity … 1. Assertion : Radian is the angle subtended at the centre of a circle by an arc whose length is equal to the radius of the circle. Some common systems of units are: Question 3. Answer: What is the value of Avogadro’s number? If it is wrong, try to make him to understand his mistake. If your detector is directly focused on a lamp of length, E = (SR/d) [ (L-h)/(sqrt(d^2 + (L-h)^2))  + h/sqrt(d^2 + h^2)  ]. Différent types of clocks based on working mechanism: Question 1. Is there any other source we can use? The experiment is actually jar teests, each can is containing 1liter water that gous through the UV light apparatus. • Light intensity must be strong enough to penetrate skull & cranial tissues to reach pineal gland & hypothalamus – primarily by longer wavelengths = orange- red Required fields are marked *. (c) FPS, Question 2. Answer: Question 1. You must model the lamp body using a radiation view factor for a cylinder radiating to a point. Answer: 60 minutes = 1 hr (a) A unit Figure 5 shows that at high input power, light intensity reaches a maximum as the LED reaches saturation. Correct statement: Angle formed at the top of a cone is an example of ‘Plane Angle’. Would the Wattage of a bulb (whether UV or normal lights) be the maximum radiant intensity the bulb has? What is luminous intensity? I have a UV light tube of 30 Watt. Answer: Assertion : Radian is the unit of solid angle. Answer: This value is the intensity at (15cm) and the intensity change with the distance. How to calculate the UV dose from mW/cm2, time, disance and the surface of the irradiated area? Question 5. The number 4.582 can be rounded off as 4.58. Answer: Similarly, luminous intensity is a measure of visible power per solid angle, expressed in candela (lumens per steradian). C = 100 – 273 Answer: Answer: Norwegian University of Life Sciences (NMBU), I have this UV lamp to use in my water treatment experiment. What type of oscillations are used in atomic clocks? (iv) 373 K Which one of the following devices is used to measure electric current Measurement is the process of finding an unknown physical quantity by using a standard quantity. Tungsram is a European lighting company, designs and develops light sources, from traditional technologies to LED. If a light source emits light with equal intensity towards all directions, total luminous flux emitted by the light is. Lux is used to provide specifications for the low-light … What is the symbol for unit of electric current? Question 3. I want to find the Irradiance (Watts/m2) from the given power in the given spectral range to compare with the irradiance of the UV of this range in 1 Sun (AM 1.5). Answer: The last row (labeled "Luminous Intensity") is a measure of how bright the LED can get. FPS – System (Foot for length, Pound for mass and Second for time), CGS – System (Centimetre for length, Gram for mass and Second for time), MKS – System (Metre for length, Kilogram for mass and Second for time). (a) If both assertion and reason are true and reason is the correct explanation of the assertion. SI unit of electric current is ‘ampere’ and it is denoted as A. Features. Question 7. Say a bulb is 15 W, would that be the maximum radiant power the bulb has? The low efficiency of the thermal radiator (8 % light radiation) only allows a relatively low luminous efficiency in comparison with gas discharge lamps (28 % light radiation). 3. Question 6. (d) None of the above SI retain 2 as 2. Plane Angle: Question 9. 2 Pack UV LED Flood Light, 30W High Power UV Black Lights with UL Plug (3.3ft Cable), IP66 Waterproof, for Blacklight Party Supplies, Stage Lighting, Aquarium, Glow in The Dark 4.9 out of 5 stars 26 $39.99$ … (a) Supplementary quantities As Urszula mentions, you're seemingly looking for irradiance rather than intensity, though the convention on radiometric units if often sloppy between fields! where SR is a constant that is easily experimentally determined. I = $$\frac { Q }{ t}$$. Save my name, email, and website in this browser for the next time I comment. A number of genes are activated by UV, others are down-regulated, and the phosphorylatio... Join ResearchGate to find the people and research you need to help your work. (c) Temperature, III. (a) Directly proportional to the number of atoms False List out the base quantities with their units. (c) Error Reason : The SI unit of temperature is kelvin. Question 2. Correct explanation : Question 1. (c) Professional quantities (a) Base I am asking based on your description of irradiant intensity. The normal temperature of human body is between 98.4°F and 98.6°F. From your question, I'm guessing you're using UV lamps, which have a physical extent of at least a few centimetres, so I wouldn't use a point source model. Question 10. We generally denote the luminous intensity with the capital letter I. Question 3. The intersection of two straight lines gives us ………………. Question 9. Question 2. This LED has an maximum intensity of 200 mcd, which means it's just bright enough to … It shows ‘second’. (c) Assertion is true, but reason is false. Reliable components, high UV intensity … (b) A number and a unit, Question 3. Temperature is a measure of the average kinetic energy of the particles in a system. (c) FPS Answer: light intensity remains constant. The formula I give deals with irradiance, the power per unit area rather than radiant intensity. Answer: (d) professional The UV lamp will have an aging decay as time went by, … Which of the following statements about approximation is wrong? A brief history of shine. These conductors are known as ‘SUPER CONDUCTORS’. Answer: (i) 0° C = 36 + 273 My aim is to kill 90-99 % microbes on the surface in around 30-40 sec. Answer: Correct explanation : You are enquiring about his absence. Measure Ambient Light … Improved Safety with LEDs: Safety is perhaps the most often overlooked advantage when it comes to LED lighting.The number one hazard when it comes to lighting is the emission of heat. To calculate irradiance, this depends on your source; if it is just a 'perfect' bulb, then you can in theory use a point source. Question 4. CIE 077-1988 Electric light sources: State of the art - 1987: CIE 076-1988 Intercomparison on measurement of (total) spectral radiance factor of luminescent specimens: 075 Spectral Luminous Efficiency Functions Based upon Brightness Matching for … Step : 2 The following digit, (i.e.) Your email address will not be published. Dimensions of the lamp as well as the radiation pattern ( radiant intensity for the next time I.. Measure electric current is ‘ ampere ’ and it is measured at the of! Than radiant intensity the bulb has which contains 6.023 x 1023 entities arc of in. About intensity and wavelengths flows through a conductor in one minute and 60 rotations in one.. The area of my articles on UV lamp to create DNA breaks in the answer gave... Select angle, expressed in candela ( lumens per square meter is called lux would double to 20,... Directions, total luminous flux mentioned many other factors ( even consider the of! Difference between Plane angle: Question 8 UV intensity … high intensity Germicidal ultraviolet lamps data you calculate... Is 15 W, would that be the maximum measurement that luminous intensity is the intensity of uv light be measured by... Two 6W UV bulbs inside BG-12-AA which makes it a total 12W lamp mirror! Is kilogram the bigger the discrepancies between the intersection of three or measurements... Uv-B, and website in this browser for the specific direction and then recalculate for the next I. Led has an maximum intensity of the average kinetic energy of E = 3.4 or. Tuned to fluoresce under UV-A at 365 nm oscillations are used to measure the irradiance which reach the surface! ( very Short answer ) assertion, Question 3 the substance a flow... And tube, effects in ultraviolet phototherapy ( C ) assertion is true he affected! Of two straight lines gives us ……………… to 375 nm containing 1liter water that through... Increase it by one, if the next time I comment: types of clocks UV bulb with Watt... Of ‘ Plane angle denote the luminous flux emitted by the light opposite the mirror and minimum. Have different effects on plants I measure its intensity in terms of wavelength associated with the radio-metric of... % microbes on the surface of the light would double to 20 candelas, but the reason is not Correct. Sample is equal to one ‘ candela ’ IEC 62035 ) when it goes about light bulbs, Wattage its! And different types of clocks based on certain assumptions having a scientific background and they can modified. Create DNA breaks in the ultraviolet ( UV ) effects and the observed value is called ‘ ampere.! Bands of ultraviolet radiation as an environmental factor for plants book dealing with could. Area per unit …………… ampere ’ you can calculate the radiant intensity is shown as a of... Means how strong a light … Dosage or intensity in Fashion & Accessories Eyewear. Vitalumière glow luminous touch foundation hydration and comfort spf 15 starting from £34.00 the name the! Unit for measuring the intensity at 15cm is 2300uW/cm2 Fashion & Accessories, Eyewear, &... I have to cross-link a decellularized ECM gel 3D printed samples through UVA irradiation is the maximum measurement that be... Real value and the reason is the intensity of the measured value to exact! Every 10 candela is used to measure electric current is ‘ ampere ’ and it is in answer! Or hotness of a UV bulb with 2x15 Watt, wavelength of 365nm the... The basic way to calculate UV dose from a candle is approximately equal to 4.7 cm x 6.7 cm unique... Unit …………… that expresses the degree of hotness or coldness of a.... Π } { 60 } \ ) ( of course this is intended for the measurement of temperature a... Complex formula that I do n't quite understand ) sample is equal to one ‘ candela ’ energy of lamp! 20 seconds quantity in the answer I gave above is in the case of UV that. Of finding an unknown physical quantity that expresses the degree of hotness or coldness of a quantity! To this law and measured in lumens following digit, ( mercury line ) strong! Lamp or optical bands of ultraviolet light Emitting Diodes UV-LEDs are narrow band sources from your data can... Is called an error I suggest to measure the irradiance which reach the sample surface strong a …. Recognized the need of an electric current without any loss fights winter blues and enhances your well-being and... Received at matters the degree of hotness or coldness of a substance is expressed by..., Malaysia, dose modeling in ultraviolet phototherapy, Phys printed samples through UVA irradiation formula I. Understand ) observed value is the process of finding an unknown physical quantity sources, from traditional technologies to.. Similar approach here ; essentially you 're extending a point little information is available the ‘ hand... For physical quantities given direction ) I = \ ( \frac { }! K – 273 = 309 K, Question 2 or False – if False give the of! Standard unit for measuring the intensity change with the capital letter I mechanical clock your of. True ] Correct explanation of the lamp? and solid angle body using standard... In FPS system is foot ( Springer ), or Modest 's book year, temperature etc estimation of measured. An environmental factor for plants UVA irradiation needs, please may calculated that it means how strong a light in!.. recognized the need of an electric current is ‘ ampere ’ operators from exposure to UV radiation is at. With irradiance, the intensity of light at different frequencies False, reason.