11.Electric Current through Conductors.
1]. Choose correct alternative: i) You are given four bulbs of 25 W, 40 W, 60 W and 100 W of power, all operating at 230 V. Which of them has the lowest resistance? (A) 25 W (C) 40 W (C) 60 W (D) 100 W Ans). D) 100 W ii) Which of the following is an ohmic conductor? (A) transistor (B)vacuum tube (C) electrolyte (D) nichrome wire Ans). D)Nichrome wire iii) A rheostat is used (A) to bring on a known change of resistance in the circuit to alter the current (B) to continuously change the resistance in any arbitrary manner and there by alter the current (C) to make and break the circuit at any instant (D) neither to alter the resistance nor the current Ans ). (B) to continuously change the resistance in any arbitrary manner and there by alter the current iv) The wire of length L and resistance R is stretched so that its radius of cross-section is halved. What is its new resistance? (A) 5R (B) 8R (C)...