PhysicsHardHigh School (11–12)Electricity & Magnetism › Current ElectricityJEE MainNEETAEEE (Amrita)AMUEEEAP EAPCETBCECE
Created by StemPy LabA uniform wire has resistance . Four new arrangements are made from it, with no material lost. Match each arrangement with its resistance. List-I (Arrangement) A. The wire stretched to twice its length B. A wire of the same metal and length, with twice the radius C. The wire cut in four equal pieces joined in parallel D. The wire stretched to four times its length List-II (Resistance) I. II. III. IV.
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← Five statements about free electrons in a metal wire are given. (i) The SI unit of mobility is m² V⁻¹ s⁻¹. (ii) For a fixed current, the drift speed is larger where the wire is thinner. (iii) At a fixed electric field, the drift speed is proportional to the relaxation time. (iv) The electric current is a vector, because it has a direction. (v) The random speed of the free electrons is much smaller than their drift speed. How many are correct?The figure shows how the terminal potential difference V of a cell changes with the current I drawn from it. The line passes through the two marked points. The cell is then joined to a variable resistor, which is adjusted until the power dissipated in the resistor is as large as it can be. What is that largest power? →
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