(b) Superposition theorem. Sliding the movable contact, the resistance between terminals can be varied. 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. Rheostat: A component used to regulate the electric current flowing through a circuit without changing the voltage is called Rheostat. MCQ Questions for Class 10 Science with Answers were prepared based on the latest exam pattern. One is a fixed value resistor, but the other is a variable resistor which is being used as a rheostat. * Resistance can varied in a circuit without the interruption so as to control the current. - 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! 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. Its main property is it is a power consuming element, and opposes the flow of current. c) The saturation voltage V CE for silicon transistor is same as that for germanium. Magnetic Circuit; DC Generator; DC Machine; MCQ. The unit is volts (V). If we increase the resistance of the rheostat, the flow of electric current through the light bulb decreases. 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. Voltage vs Current