l Airtel_HP 4G7:19 PM© 74%< xyz imgtopdf_3008211907008.pdf.pdf|7019. Consider the junction diode as ideal. Thevalue of current flowing through AB is:30. If1k aww+4 V-6V(a) O A(b) 10A(d) 10 A(c) 10A20. The temperature dependence of resistancesof Cu and undoped Si in the temperaturerange 300 - 400 K is best described by:(a) Linear increase for Cu, linear increasefor Si.(a) a and B both are negative(b) a is positive and B is negative(c) a and B both are positive(d) a is negative and B is positive25. If a battery of 6 V is connectedterminals of 3 m long wire ofthíckness and resistance of the or100 2. The difference of potential bethe two points separated by 50 cm31(b) Linear increase for Cu, exponentialincrease for Si.(c) Linear increase for Cu, exponentialdecrease for Si.(d) Linear decrease for Cu, linear decreasefor Si.wire will be(a) 1 V(c) 2 V(b) 1.5 V(d) 3 V21. When 5 V potential difference is appliedacross a wire of length 0.1 m, the driftspeed of electrons is 2.5 x 10 ms. If theelectron density in the wire is 8 x 10 m,the resistivity of the material is close to:(a) 1.6 x 10 Qm (b) 1.6 x 102 m(c) 1.6 x 102m (d) 1.6 x 102m26. A wire of resistance 4 2 is stretchetwice its original length. The resistanostretched wire would be(a) 22(c) 82(b) 42(d) 16 222. A current 4.0 A exists in a wire of cross-sectional area 2.0 mm. If each cubicmetre of the wire contains 12.0 x 10 freeelectrons, then the drift speed is(a) 2 x 10 ms(c) 1.04 x 10ms (d) None of these27. The electrical conductivity of thedecreases with temperature, because(a) the energy of the electrons increwith temperature(b) a metal expands on heating(c) the atoms of the metal vibrate monhigher temperature(d) metals have low specific heat(b) 0.5 x 10 m s23. Two conductors are made of the samematerial and have the same length.Conductor A is a solid wire of diameter1.0 mm and conductor B is a hollow tubeof outside diameter 2.0 mm and inside28. If a wire is stretched to make it 0.1% lonits resistance will(a) increase by 0.2%(b) decrease by 0.2%(c) decrease by 0.05%(d) increase by 0.05%diameter 1.0 mm. Find the resistance ratioR/R, measured between their ends.(a) 3(b) 2(c) 1(d) 0.529. Two wires A and B of the same ma24. The resistance R of a conductor varieswith temperature t as shown in the figure.If the variation is represented by R, = R(I + at + Bt), thenhaving radii in the ratio 1: 2 andcurrents in the ratio 4:1. The ratiospeeds of electrons in A and B is(a) 16:1(c) 1:4(b) 1: 16(d) 4:1

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19. Consider the junction diode as ideal. The value of current flowing through AB is: 1k a www +4 V -6V (a) OA (b) 10A (d) 10 A (c) 10'A 20. The temperature dependence of resistances of Cu and undoped SI in the temperature range 300 - 400 K is best described by: (a) Linear increase for Cu, linear increase for Si. (b) Linear increase for Cu, exponential (a) a and B both are negative (b) a is positive and B is negative (c) a and B both are positive (d) a is negative and B is positive 25. If a battery of 6 V is connected terminals of 3 m long wire of thíckness and resistance of the 100 2. The difference of potential be the two points separated by 50 cm 31. increase for Si. (c) Linear increase for Cu, exponential decrease for Si. (d) Linear decrease for Cu, linear decrease for St. wire will be (a) 1 V (c) 2 V (b) 1.5 V (d) 3 V 21. When 5 V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is 2.5 x 10 ms. If the electron density in the wire is 8 x 10 m, the resistivity of the material is close to: (a) 1.6 x 10 a m (b) 1.6 x 10 am (c) 1.6 x 102 m (d) 1.6 x 102 m 26, A wire of resistance 4Q is stretche twice its original length. The resistar stretched wire would be (a) 20 (c) 82 (b) 42 (d) 16 2 22. A current 4.0 A exists in a wire of cross- sectional area 2.0 mm. If each cubic metre of the wire contains 12.0 x 10 free electrons, then the drift speed is (a) 2x 10 ms (b) 0.5 x 10ms (c) 1.04 x 10ms (d) None of these 27. The electrical conductivity of the m decreases with temperature, because (a) the energy of the electrons incre with temperature (b) a metal expands on heating (c) the atoms of the metal vibrate mon higher temperature (d) metals have low specific heat 28. If a wire is stretched to make it 0.1% loy its resistance will 23. Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1.0 mm and conductor B is a hollow tube of outside diameter 2.0 mm and inside diameter 1.0 mm. Find the resistance ratio R/R measured between their ends. (a) increase by 0.2% (b) decrease by 0.2% (c) decrease by 0.05% (d) increase by 0.05% 29. Two wires A and B of the same mal (a) 3 (b) 2 id) 0 5