PhysicsAdvancedHigh School (11–12)Electricity & Magnetism › Current ElectricityNEETAEEE (Amrita)AMUEEEAP EAPCETBCECECMI Entrance
Created by StemPy LabAssertion (A): When a switch is closed, a lamp lights almost at once, although the free electrons in the copper connecting wires drift at a fraction of a millimetre per second. Reason (R): The free electrons in a metal move at speeds far greater than their drift speed, because of their random thermal motion.
← All Quizzes
← The figure shows three identical bulbs, an ideal battery and a switch S, open at first and then closed. Take each bulb's resistance as constant and brightness as proportional to power. (i) With S open, A and B are equally bright. (ii) On closing S, A becomes brighter. (iii) On closing S, B becomes brighter, since the battery supplies more current. (iv) On closing S, the battery current becomes 4/3 of its first value. (v) On closing S, A is only twice as bright as B. How many are correct?In a Wheatstone bridge, the arms P and Q are in series on one side and R and S are in series on the other, with P and R meeting at one battery terminal. The galvanometer joins the junction of P and Q to the junction of R and S. Statement I: If the battery and the galvanometer of a balanced bridge are interchanged, the galvanometer shows a deflection. Statement II: A bridge with P = 10 Ω, Q = 20 Ω, R = 30 Ω and S = 50 Ω is balanced. →
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