Which of the following theorem is used for the analysis of a transistor circuit (a) Thevenin’s theorem. Dec 10,2020 - The rheostat is used in the circuit to :a)increase the magnitude of current onlyb)decrease the magnitude of current onlyc)increase or decrease the magnitude of currentd)none of theseCorrect answer is option 'C'. Blocked rotor test on induction motors is used to find out (a) leakage reactance (b) power factor on short circuit (c) short-circuit …
However, the material may have large thermo-emf and a large value of temperature coefficient of resistance.But the material should meet to some special requirement such as high permissibly working temperature and low cost. When cells are connected in parallel the total value of the cells is the same as each individual cell. Science Lab Manual Class 10 Experiment – 1. Rheostat is generally used in the applications where high voltage or current is required. Multiple Choice Question (MCQ) of Electronics page-17:241. In technical terms, the potentiometer and rheostat represent two different configurations in which a variable resistor can be used. (c) Norton’s theorem. Students can solve NCERT Class 10 Science Electricity Multiple Choice Questions with Answers to know their preparation level. It is used to control the electrical resistance of a circuit without interrupting the flow of current. Potentiometer (POT) With all three terminals connected to the circuit, pots are generally used … The resistances generate huge losses and generate heat in the system. For two 1.5 V cells in parallel, the voltage stays at 1.5 V, but the life (current capacity) of the battery is doubled. Two terminal trimmers are available, although in most cases three terminal potentiometer trimmer is used as a two terminal rheostat. Aim Take the quiz to find out! Multiple Choice Question (MCQ) of Electronics page-17:241. Generally, the term potentiometer is used to represent a three-terminal variable resistor. 76. 8.2 Marking on Packaging The requirements for marking specified at 7 shall IS 8622 : 1999 marked current of the rheostat. These motors are used where the motor speed below the base speed is required as they cannot be operated above the base speed. (Round the FINAL answer to three decimal places.) « Back CONTENTS Next » 1. Rheostats are used in dim lights to change the intensity of light. Rheostat is an adjustable or variable resistor. Brief History Low temperature coefficient of the resistance used for extending the range of a voltmeter (a) reduces inaccuracies due to the temperature variations (b) enables instrument to work at high temperatures (c) increases the least count of the instrument (d) enlarges the scale of reading. While the rheostat is a two terminal device that forms connection with one end and the wiper or slider only. • If a parallel circuit is opened in the main line, the current, (a) increases in the branch of the lowest resistance, (d) is zero in the highest resistive branch, 11. 3. Can you explain this answer? The ammeter is connected in series circuit (c) The rheostat can only increase the resistance in electric circuit (d)The single key is used to switch on/off the electric circuit . We have Provided Electricity Class 10 Science MCQs Questions with Answers to help students understand the concept very well. A rheostat differs from potentiometer in the respect that (A) rheostat has large number of turns (B) rheostat offers larger number of tappings (C) rheostat has lower wattage rating (D) rheostat has higher wattage ratings. As shown, the electricity must first flow through the HOA switch before it can energize the coil of the motor contactor. Calculate the circuit current with the rheostat set at maximum value (1,000 ohms). The word rheostat was coined about 1845 by Sir Charles Wheatstone , from the Greek ῥέος rheos meaning "stream", and - στάτης - states (from ἱστάναι histanai , " to set, to cause to stand") meaning "setter, regulating device", [6] [7] [8] which is a two-terminal variable resistor. MCQ OF ELECTRICITY . Your name: Your email: Your Comments: Enter the code above here : Can't read the image? A rheostat is a type of variable resistor, whose resistance can be changed for varying the amount of electric current flowing through an electrical circuit. Free PDF Download - Best collection of CBSE topper Notes, Important Questions, Sample papers and NCERT Solutions for CBSE Class 10 Physics Electricity. When it is used in a control circuit, it looks like Figure 3-18. In a parallel circuit there is more than one path for the current to flow along. Rheostat: A component used to regulate the electric current flowing through a circuit without changing the voltage is called Rheostat. If we … * Rheostat is a variable resistance which is used in the circuit to control the current. In this method of speed control of three phase induction motor rheostat is added in the stator circuit due to this voltage gets dropped .In case of three phase induction motor torque produced is given by T ∝ sV 2 2. The circle diagram for an induction motor cannot be used to determine (a) efficiency (b) power factor (c) frequency (d) output Ans: a. Click here to refresh As you can see, motor speed may be made variable using a series-connected rheostat to change total circuit resistance and limit total current. 1․ A power system has three synchronous generators. b) The saturation voltage V CE for germanium transistor is more than silicon transistor. The entire NCERT textbook questions have been solved by best teachers for you. Class 10 Science MCQs Chapter 12 […] It is most often designed with a ceramic core. Resistance is a passive element in electrical and electronic circuits. Free PDF Download of CBSE Class 10 Science Chapter 12 Electricity Multiple Choice Questions with Answers. rheostat (rē`əstăt'), device whose resistance to electric current depends on the position of some mechanical element or control in the device.Typically a rheostat consists of a resistance element equipped with two contacts, or terminals, by which it is attached to a circuit: a fixed contact at one end and a sliding contact that can be moved along the resistance element. The following circuit contains two resistors. Sliding the movable contact, the resistance between terminals can be varied. Magnetic Circuit; DC Generator; DC Machine; MCQ. a) The saturation voltage V CF of silicon transistor is more than germanium transistor. The unit is volts (V). c) The saturation voltage V CE for silicon transistor is same as that for germanium. Rheostat, adjustable resistor used in applications that require the adjustment of current or the varying of resistance in an electric circuit.The rheostat can adjust generator characteristics, dim lights, and start or control the speed of motors.Its resistance element can be a metal wire or ribbon, carbon, or a conducting liquid, depending on the application. Rheostat is used for varying higher values of electric current. b) The saturation voltage V CE for germanium transistor is more than silicon transistor. People may be most familiar with the rheostat in the form of a dimmer or slider which is used to vary the intensity of a light. Its main property is it is a power consuming element, and opposes the flow of current. a) The saturation voltage V CF of silicon transistor is more than germanium transistor. It has several applications in both DC and AC circuits. Preset Rheostat: When rheostats are used in a printed circuit board, they are used as trimmers or preset rheostats. * Resistance can varied in a circuit without the interruption so as to control the current. Published by Houghton Mifflin Harcourt Publishing Company. Check the below NCERT MCQ Questions for Class 10 Science Chapter 12 Electricity with Answers Pdf free download. The turbine-governor characteristics corresponding to the generators are P 1 =50(50 − f), P 2 = 100(51 − f), P 3 = 150(52 − f) Where, f denotes the system frequency in Hz, and P 1, P 2, P 3 are the power outputs of the turbines in MW. The most common way to vary the resistance in a circuit is to use a rheostat. To get through the switch, the switch must be in the hand or auto position. The rheostat which is used to vary the resistance per phase causes unbalancing in rotor. of the rheostat till the ammeter reads the also be marked on packaging of rheostat. Enter Your Suggestion/Comments Here. Rheostat is the instrument used to control the current in an electric circuit. We hope the given MCQ Questions for Class 10 Science Electricity with Answers will help you. Rheostat has 3 terminals and usually consist of a resistive wire wrapped to form a toroid coil with a wiper that slides along the surface of the coil. - 823449 A rheostat differs from potentiometer in the respect that, (B) rheostat offers larger number of tappings, Submit your documents and get free Plagiarism report, Your solution is just a click away!

Another way to prevent getting this page in the future is to use Privacy Pass. It is always connected in parallel in the circuit. MCQ Questions for Class 10 Science with Answers were prepared based on the latest exam pattern. Test the rheostat in this condition for an hour and check that there is no deterioration of wire or Assuming generators and transmission network to be lossless, the system frequency for a load of 700 MW is Mechanical Engineering; Electrical Engineering; Electronics Engineering; Civil Engineering; Top. The third one is not connected. Both speed and torque can be controlled by armature voltage control, armature rheostat control, and chopper control methods. In this post, you'll learn the 3 essential differences between both. In a rheostat, only two lead terminals (One fixed and one moving) are connected to the circuit. It is used to control the electrical resistance of a circuit without interrupting the flow of current. One is a fixed value resistor, but the other is a variable resistor which is being used as a rheostat. In case of a large machine the size of the rheostat will be large and in such case it is not easily portable. c) The saturation voltage V CE for silicon transistor is same as that for germanium. Which of the following statement is true? | EduRev Class 10 Question is disucussed on EduRev Study Group by 170 Class 10 Students. 77. It is used to change the resistance in the circuit. (b) Superposition theorem. MCQ Questions for Class 10 Science with Answers was Prepared Based on Latest Exam Pattern. Commonly available resistors have a fixed value and are used for restricting smaller values of electric current. (d) Reciprocity. Trimmers are nothing but a small rheostat, mostly used in calibration circuits. If we increase the resistance of the rheostat, the flow of electric current through the light bulb decreases. Voltage vs Current If you have any query regarding CBSE Class 10 Science Chapter 12 Electricity Multiple Choice Questions with Answers, drop a comment below and we will get back to you at the earliest. In its simplest configuration, a potentiometer may be used as a rheostat by simply using the wiper terminal and one of the other terminals, the third terminal left unconnected and unused: 5. It requires more maintenance, hence the cost associated with it is more. It has variable resistance. Which of the following statement is true? Rheostat. A rheostat is a device which is used to vary the resistance in an electrical circuit without interrupting the circuit. Adding Rheostat in Stator Circuit.