MCQ Questions for Class 12 Physics with Answers were prepared based on the latest exam pattern. There are all sorts of variations on this theme, such as seeing how much ac current flows through the capacitor for a particular ac voltage, in case you have an ordinary ac meter to measure current and voltage and some suitable source of ac voltage. The intrinsic region has a high resistance which can be calculated at zero bias by the following equation: (2 . The number of electrons that constitute 1 A of current is: These days, when I use touch screen technology I feel a strange sensation in my fingertips (much like the knee thing) and it gives me the gut feeling that something isnt right. (b) 3 (a) 0.3 A A milliammeter of resistance 2.5 ohm and a full deflection of 50mA is to be used to measure a potential difference of 50V. (b) super-conductor Peace, (c) 0.2 A You don't need the capacitance to ground provided by the body. Bear in mind that this is a "best case" scenario (clean, dry skin) from the standpoint of electrical safety and that this figure for voltage represents the amount necessary to induce tetanus. which is the most dangerous low voltage or high voltage? about 10,000 ohms How are electrical conductance and resistance of an object related? How would you measure the capacitance, using a cheap way if possible? (d) It draws heavy current from external circuit, Answer: (c) It does not draw current from external circuit, Question 50. (a) temperature When electrical energy of high voltage gets into the human skin, the resistance is reduced to 500 ohms. You also have the option to opt-out of these cookies. A rough value for the internal resistance of the human body is 300-1,000 Ohms . resistance : ohm capacitance : henry inductance : farad lumen : steradian According to the fuse law, the current carrying capacity varies as 1/(diameter) 2 1/diameter Hi, thank you for your help. Additional Information Step potential: It . (c) Thomson That means the voltage and current through a normal human body is always less the 40V and 15mA. In the above question, the conductance: The cookie is used to store the user consent for the cookies in the category "Other. The correct answer is option D) 100,000 ohms. (c) \(\frac{1}{2}\) Consistency of the skin, that is, whether it is dry or moist. (c) 3 108 ms-1 Under dry conditions, the resistance offered by the human body may be as high as one mega ohms. If you happen to already have an oscilloscope with a high-impedance input, you can charge up the capacitor with a battery and then let the charge drain off through a big resistor while monitoring the voltage on the scope. 3 others of my piers all read 87k olhms or greater. (a) It is a null method Electrical resistance shares some conceptual parallels with mechanical friction. The skin Where , , are positive constants. Stopping a laptop though is a different matter. (d) 10 W, Question 23. Peter, University of Illinois at Urbana-Champaign. Hence, current through bulb (IB) This makes the assumption that body . If it works with de-ionized water I bet it's capacitance, since the resistivity is so high. Assume (E = 7.32 V and R=6.42 ohm). Yes, the on-off switch goes to a sealed electronic box, so I agree that that part of the circuit doesn't take the full current of the motors. temperature heating a wire increases its resistance. Agree resistance of human body is 120 ohm. The Human body has different resistances, when dry, resistance is . I want to create the bodies electric field mechanically with no human connection. Thus, we use the . The drain time (to about 40% of the initial voltage)is RC, the resistance times the capacitance. (c) resistance will be halved and the specific resistance will be doubled In order to find current through bulb, first we have to calculate its resistance (RB). On seeing the red signal of traffic at 27m ahead on the road, the driver applied brakes and the bus stoppe (c) It does not draw current from external circuit . Question 12: The resistance of a human body is about: (a) 12 (b) 120 (c) 12 K (d) 120 M . Resistivity. Under wet condition, the resistance is reduced to 1000 ohms. 4 What is average resistance of human body? A stylus pen is a conduit for the bodies electric field. One other page in fact pointed out the AC/DC difference but did not explain the reason (epidermis as dieletric)- now it makes sense. What is average resistance of human body? In short, Resistance of human body is 2200 ohms. It is more easier to solve. (a) H1 = H2 More than 99% of the . An electrical shock may cause burns, or it may leave no visible mark on the skin. Enter your email address to subscribe our blog. For instance, men tend to have lower resistance than women. View Answer Wet or broken skin may drop the body's resistance to 1,000 ohms," adding that "high-voltage electrical energy quickly breaks down human skin, reducing the human body's resistance to 500 ohms". (d) None of these, Question 26. What kind of skin has the higher resistance to electricity? Thanks for all your thoughtful points. Is the respiration process takes place in each cell of the human body? Question: I would like to control my IPad touch screen without touching it. MCQ Questions for Class 12 Physics with Answers, Concise Mathematics Class 10 ICSE Solutions. 10. But let me be more direct and honest: Given three equal resistors, how many different combinations (taken all of them together) can be made? Problem 1: A person touches live wire of a 100 watt closed circuit. This program is supported in part by the National Science Foundation (DMR 21-44256) and by the Department of Physics. Rebecca, If he comes into contact with 120-V AC, a current I Most of the body's resistance is in its dry skin. If the body having higher resistance then the damage will be lower. ). (d) 3 1010 ms-1, Question 2. (a) joule Electrical capacitance is defined by the amount of static charge on a body divided by the voltage of the body with respect to some reference ground. These cookies will be stored in your browser only with your consent. These cookies track visitors across websites and collect information to provide customized ads. An electric current of 1 mA through the human body is just barely detectable. The only thing that's needed is to have some conductor or very high dielectric constant material to perturb the field coming from the screen. (d) None of these, Question 35. Human body static dissipator measures the resistance of human body and displays 'Pass or Open' depending on the measured value of resistance. The internal resistance of the body is approximately 300 , whereas values of body resistance including skin range . What is the difference between Earthing and Grounding? But then an expanding web of side effects ('consequences you didn't think of,' quips biologist Garrett Hardin, 'the existence of which you will deny as long as possible') started to appear. What's particularly odd is that 47k is a standard resistor value. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". (a) It has a wire of high resistance However, you may visit "Cookie Settings" to provide a controlled consent. (a) resistance will be doubled and specific resistance will be halved (c) H1 > H2 (a) resistance What is the function of a choke in tube light? In my last post, I talked about the Electrical safety procedure and precaution when you are doing work. (b) 120 The value varies because there are so many factors involved. What is the resistance across A and B in the network in Fig.? The internal resistance of human body is around 300-1000 ohms. (d) H1 H2, Question 55. (a) 3 104 ms-1 JAMB Syllabus 2023/2024 for Physics Questions and Answers This JAMB Syllabus for Physics aims to prepare the candidates for the Unified Tertiary Matriculation Examination (UTME). Top electrical engineering interview questions. 200 O B. (d) thermistor, Question 34. (a) 500 W Spraying DDT seemed to work: Mosquitoes died, and malaria declined. Thus the shaft-to-shaft connection would be in series with the on-off switch, as you found, but not in series with the motor. (adsbygoogle = window.adsbygoogle || []).push({}); Why all the voltage levels are multiples of 11 kV? The ampere (A) is the common unit of current equal to 1 C/s and the symbol for current is I. The units for current are C/s for the amount of charge (C) that travels per unit time (s). false. (c) 10 (d) \(\frac{r}{n^2}\), Question 52. (d) None of these, Question 31. This may be attained by using rubber gloves, rubber mats and like others. Neil Postman writes about this (as it relates to technology) fairly well in his book Technopoly. Now I will Generally, a power surge can follow in any wire in your very new or old home and threaten any device plugged-in Safety First and it does not matter where you stay. It does not involve ohm's law. Join The Discussion. (a) H1 = H2 Affordable solution to train a team and make them project ready. Depending on the person, the resistance of dry skin is usually between 1,000-100,000 Ohms. It depends on the body structure. In order to make this problem easy, lets draw a resistive circuit of given diagram. Now, with a maximum permissible earth resistance of 5 Ohms . More current will flow through you if your hands or body are wet because it makes a better electrical contact. (b) more Yes, the scientific method is in general a very helpful tool of great value. (c) 1 : 1 The correct option is D. 1000 o h m s. According to the National Institute of Occupational Safety and Health, the resistance of the human body is 1000 o h m s , under wet conditions. It's okay to disagree with the standard response. The cookie is used to store the user consent for the cookies in the category "Performance". When wet because of sweat or water, resistance is only 1,000 ohms. (c) \(\frac{1}{2}\) In short, Resistance of human body is 4000 ohms. (c) It has four resistances (c) lmax = \(\frac{^2}{2}\) It's educational. When does an Ohm have an electrical resistance? The ratio of the velocity of electrons in the conductor be : Touch screens just provide a conductive surface, aninsulator, and a way to measure the local change in capacitance caused by your finger. When human body has static charge, the resistance is typically above 1 Mega Ohm. (b) copper has low electrical resistivity Current flow is obviously higher as the resistance goes down. While dry skin may have a resistance of 5,000 to 50,000 ohms (which can easily be checked with an ohmmeter), water or perspiration will reduce this resistance considerably. A uniform w ire connected across a supply produces heat H per second. RD Sharma Solutions , RS Aggarwal Solutions and NCERT Solutions. If you could show that there's really a sensation associated with using touch screens, you might be able to get someone interested in studying it more. Just like for the resistors used in electronics, the resistance of a persons arm depends on the arms length and diameter. First and foremost is the resistance of the skin. Remember, ohms is the unit of measure of a material's resistance or impedance to current flow. Resistance is the opposition that a substance offers to the flow of electric current . (c) specific conductance 1000 ohms. However the amount of resistance is different with dry and wet skin. Industry tends to move things forward without testing things well enough, and without testing them in terms of systemic impact. (b) 5 Solution: This problem is almost similar to above one. RB = 400 . The example of a non-ohmic resistance is: Which is correct poinsettia or poinsettia? 5 What is the highest voltage a human can withstand? This correlates to an impedance of about 13 megohms at 60 Hz, which corresponds to a minimum of 9 uA at 120 VAC to ground. material, eg copper, has lower resistance than steel. The body has resistance to current flow. The cookie is used to store the user consent for the cookies in the category "Other. (c) magnetic field (c) thermocouple Something about the effects of ac vs dc on the body. Essentially it is the skin, along with such factors as area of contact, tightness of contact, dryness or wetness of the skin, and cuts, abrasions, or blisters that introduce the variables. But, as a scumbag author, I'm well aware that this is a regularly used resistance value in different standards, datasheets, and . Considering 100mA as fatal current and 400 ohms as body resistance, the voltage may be calculated by this equation. As RB and RH are connected in parallel, so 0.55 current will divided into two parts. It is a "Superlative" Misquito pre-assembled boat made in China. Therefore, usually, the normal resistance of the body is varied from 300 - 1000 ohms. A rough value for the internal resistance of the human body is 300-1,000 Ohms. 4. Under certain circumstances, even a small amount of electricity can be fatal. If we touch the two electrodes of a battery with . US English. 1. It does not store any personal data. This cookie is set by GDPR Cookie Consent plugin. Answer: Option B . It is stretched to /i times its original length. (a) a high resistance in parallel Three 6 ohm resistors are connected to form a triangle. An electric current can cause muscular contractions with varying effects. This website uses cookies to improve your experience while you navigate through the website. There are a lot of factors involved and not every person has the same electrical resistance. The resistance of an aluminium wire is/i. The supply voltage is 220 volt and total current flow in a circuit (when touches) is 0.60 ampere. Current flow is obviously higher as the resistance goes down. If you have any queries regarding Current Electricity CBSE Class 12 Physics MCQs Multiple Choice Questions with Answers, drop a comment below and we will get back to you soon. More than 99% of the body's resistance to electric current flow is at the skin. (b) R/n (b) 20 It also varies from person to person. Resistance of human body in dry condition a) 10 ohm b) 1000 ohm c) 10000 ohm d) 100000 ohm . (b) 2 (c) decrease in length Their styli usually aren't conductive, so they won't work with the Ipad. RH = 220/ 0.1 Problem 2: A person touches live wire of a closed circuit. There are several factors that affect the resistance of a conductor; What happens to your body when you are electrocuted? (b) doubled In either case, an electrical current passing through the body can cause internal damage, cardiac arrest or other injury. . Not like existing styli. (a) conservation of energy I didn't know that. Some quite elaborate ways of testing it too. Don't use voltage from standard outlets. The fatal voltage for a human body is 40 Volts and above. (a) Joule Thiru - Laptops cause sperm count reduction in men. Solution: The circuit shown in diagram is similar to a parallel resistive circuit. . Remember, ohms is the unit of measure of a materials resistance or impedance to current flow. (b) H1 < H2 However, you may visit "Cookie Settings" to provide a controlled consent. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. I'm still surprised that either your hand across the brass shafts, or them being in the water will activate the boat electrical system. (b) It is based on Kirchhoffs laws For death to occur, the human body must become part of an active electrical circuit having a current capable of overstimulating the nervous system or causing damage to internal organs. copperheads civil war significance; sebring raceway 2022 schedule; buffalo bills zubaz winter hat; resistance of human body is 120 ohm . Human skin resistance varied from 400 ohms for wet skin to 500000 ohms for dry skin. (b) Onnes Let us consider RB is resistance of bulb and RH is Resistance of human body. (b) 4 The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". You didn't answer follow up #9 the way he wanted. I was researching what the total electrical resistance of the human body was and got some quite far ranging values. For example the arm to arm resistance will be different from resistance measured from arm to foot.
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