What happens to resistance of a conductor when its area of cross-section is increased? Ans. Resistance decreases Question 2 The charge possessed by an electron is 1.6x10-19 coulombs. Find the number of electrons that will flow per second to constitute a current of 1 ampere. Ans. Question 3 Name the instrument used to measure electric current in a circuit. Ans. Ammeter Question 4 In the following table the values of current I flowing in a given resistor for the corresponding
Premium Electric current Electrical resistance Ohm's law
voltage (as determined by Ohm’s law)‚ provided the temperature remains constant and the material remains in the same shape and state. Copper is the most common material used for electrical.Silver is the best conductor‚ but it is expensive. It has a resistivity of 1.6×10−8 Ω⋅m. Because gold does not corrode‚ it is used for high-quality surface-to-surface contacts. However‚ there are also many non-metallic conductors‚ including graphite‚ solutions of salts‚ and all plasmas. There are even conductive polymers
Premium Electric current Electricity Copper
magnetic field. (a) Superconductors (b) Semiconductors (c) Magnetic field (d) None of the above 4. -----------------are used in heating elements‚ precision instruments‚ incandescent lamps‚ and motor starters. (a) Low Resistivity Materials (6) Medium Resistivity Materials (c) High Resistivity Materials (d) None of the above 5. Mercury as a ________ contact material is a metal liquid. (a) an Electric (b) metallic (c) liquid (d) gas 6. -------------- is not a Semiconductor.
Premium Atom Electron Proton
devices rather than pure metals. Give one reason. 8. An electric geyser has the ratings 2000W‚ 220V marked on it. What should be the minimum rating‚ in whole number of a fuse wire that may be required for safe use with this geyser? 9. The electrical resistivity of few materials is given below in ohm-meter. Which of these materials can be used for making element of a heating device? A. 6.84 x 10-8 B. 1.60 x 10-8 C. 1.00 x 10-4 D. 2.50 x 1012 E. 4.40 x 10-5 F. 2.30 x 1017 10. Where do we connect a fuse:
Premium Electricity Electrical resistance Electric current
flows in a circuit is electrons‚ but electrons are I= negatively charged and current is positive. The current always dt points the opposite direction as the electrons. The unit of Current is the Ampere and is defined to be one coulomb per second. Resistivity The resistance of a resistor depends on both the material the resistor is made of and the geometry of the resistor. The longer the resistor the greater the distance electrons must travel and the more times they can collide with other
Premium Electric current Ohm's law Electrical resistance
Batteries‚ Resistance and Current “Battery-Resistor”: Check “show battery” and “show cores”‚ watch what happens‚ adjust some variables 1. Why do electrons (blue dots) move? Draw a diagram of the battery‚ label the flow of electrons. The flow of current (+) is opposite; draw this and note if toward or away from + terminal of the battery. The electrons move because of the battery voltage. The current flows in the opposing direction of the electrons and the electrons flow towards the positive
Premium Electric current Electrical resistance Ohm's law
the algebraic definitionsabove to produce a variety of other formulae‚ including ’Power = Current × Voltage’ * Ohm’s Law states that ’Voltage = Current × Resistance’. We can use this to produce two more definitions of Power. Resistance and Resistivity * Resistance it the opposition to the passage of current within a component. The Resistance of a component decides how much voltagewill be dropped across it for a particular current. * Resistance is measured in Ohms (Ω). According to Ohm’s
Free Atom Electron Chemical bond
losses in the cable ’s metallic conductors. Temperature also has effects the resistivity of the conducting surface. Resistivity is a "bulk property of material describing how well that material inhibits current flow. This is slightly different from resistance‚ which is not a physical property. If one considers current flowing through a unit cube of material (say‚ a solid metal cube that measures 1 meter on each side)‚ resistivity is defined as the voltage measured across the unit cube length (V/m) divided
Premium Cable Coaxial cable Electric current
law became publicly known in 1827 and states that a circuit’s resistance is 1 ohm if a 1-volt voltage make 1 amp of current. According to Ohm’s law‚ a circuit’s resistance is equal to its voltage divided by the amount of current. • RESISTIVITY The measure of the potential electrical resistance of a conductive material. It is determined experimentally using the equation [pic] = RA/l‚ where R is the
Free Resistor Electrical resistance Ohm's law
and Mechanical Properties * Density * About the same as carbon steel * Conductivity * Poor conductors of both heat and electricity * Thermal conductivity of stainless is about half of carbon steel * Electrical resistivity of stainless steel can be as much as 6 times as much as carbon * Expansion * Austenitic (300 series): coefficient of thermal expansion is up to 50% greater than carbon steel * Modulus of elasticity * Slightly lower than carbon
Premium Stainless steel Steel Iron