Physics Exam - PDF

1 Choose The Correct Answer:- 1. In the given graphical relation, the change in the quantity of charges flowing through the conductor within certain time interval, the current intensity passing through the conductor is…Ampere. a. 0.5 b. 1 c. 1.5 d. 2 2. An electric current of 3 A is passing thr...

1 Choose The Correct Answer:- 1. In the given graphical relation, the change in the quantity of charges flowing through the conductor within certain time interval, the current intensity passing through the conductor is…Ampere. a. 0.5 b. 1 c. 1.5 d. 2 2. An electric current of 3 A is passing through a conductor, so the number of electrons flowing through a given section in the conductor in 8 seconds is…Electrons. a. 1.5 × 1018 b. 1.5 × 1019 c. 1.5 × 1020 d. 1.5 × 1021 3. Through the interval of 8 seconds, what is expressed in the two relations? 2 4. A voltage of 120 volt is needed to transfer a stream of 6.5×1018 electron through a conductor within 2 seconds, the resistance of such conductor is… a.230 b.121 c.57.7 d.38.4 5. A conductor of 20 resistance, carrying current of 1 Ampere, as the same conductor carries 2 Ampere, its new resistance value is… a. still 20 b. 40 c. 10 d. 80 6. Which wire has the highest resistance of all, using the opposite graph… a. x b. y c. z d. l 7. Using the given graphical relation, the ratio:- 𝒕𝒉𝒆 𝒆𝒍𝒆𝒄𝒕𝒓𝒊𝒄 𝒓𝒆𝒔𝒊𝒔𝒕𝒂𝒏𝒄𝒆 𝒐𝒇 𝒄𝒐𝒏𝒅𝒖𝒄𝒕𝒐𝒓(𝑨) =… 𝒕𝒉𝒆 𝒆𝒍𝒆𝒄𝒕𝒓𝒊𝒄 𝒓𝒆𝒔𝒊𝒔𝒕𝒂𝒏𝒄𝒆 𝒐𝒇 𝒄𝒐𝒏𝒅𝒖𝒄𝒕𝒐𝒓(𝑩) a. 0.33 b. 1 c. 3 d.3.3 8. A wire of length 30 meter and C.S.A 0.3cm2 connected in series to a source of D.C, ammeter, the P.d is at its terminals is measured using voltmeter 0.8 V , the current intensity is 2 A, the wire's conductivity=… a. 2.5×106 -1.m -1 b. 1.5×106 -1.m-1 c. 3.5×106-1.m-1 d. 4.5×106-1.m-1 3 9. A power station is connected to a factory at distance of 2.5 Km by two wires of P.d 240 volt at the station and 220 volts at the factory, if current at the factory is 80 A, resistivity of wire is 1.57×10 -8.m. The resistance per unit length for the wire … a. 5×10 -5 /m b. 1.5×10 -5 /m c. 2.5×10 -5 /m d. 3.5×10 -5 /m 10. A thread of mercury of length 106.3 cm, its sectional area is 1 mm2 , has a resistance of 1 , the specific resistivity of mercury=… a. 1.063×10 -6..m b. 1.063×10 -7.m c. 9.4×10 -6.m d. 9.4×10 -7.m 11. As the resistivity of a conductor is 0.5.m so its product with conductivity equals.. a. 0.5 b. 1 c. 2 12. On increasing the length of a wire to its double and decreasing its radius to half, its resistance becomes … a.eight times b. double c. unchanges 13. On increasing the length of a conductor its conductivity… a. increase b. decrease c. unchanges 14. A conductor of a uniform cross-section, its length 20 m and its resistance is 108 , another of the same material its length 5m, and of cross-sectional area equal three times the cross-sectional area of the first. The resistance of the second conductor equal… a. 84 b. 27 d. 9 15. For a resistance wire, on increasing its length to double and decreasing its sectional area to half, its resistance value becomes… a. double its value b. Four times its value c. Unchange 4 16. Two copper wires of same length, the cross-sectional area of the second wire is three 𝑹𝟏 times as that of the first wire. So, the ratio 𝑹𝟐 equal.. a. 3:1 b. 1:3 c.6:1 d. 1:6 17. The figure shows four uniform conductor made of the same material, but of different dimensions. Their correct arrangement ascendingly according to their electrical resistance, starting from the least to the greatest resistance is… a. D→B→A→C b. B→C→A→D c. C→A→B→D d. D→A→C→B 18. A current of (I) intensity passes in a conductor of (L) length and its section area = (3A), when the same battery is used with a different conductor of the same material as the first one, it was found that a current of (3I) passes in it, this due to … a. The second conductor is of length(2L) and its cross section area = (18A) b. The second conductor is of length (3L) and its cross section area = (3A) c. The second conductor is of length (18L) and its cross section area (2A) 𝟏 𝟏 d. The second conductor is of length (𝟐 𝑳) and its cross section area (𝟑 𝑨) 19. Two wire made of similar material, the diameter of the first is 3 times the diameter of the second wire, the resistance of the second wire is 4 times the resistance of the first wire. So, the length of the second wire is…the length of the first wire. 𝟑 𝟕𝟐 𝟒 𝟑𝟔 a.𝟒 b. c.𝟗 d. 𝟐 𝟑 20. The average current during a lightning strike between a cloud and the ground is 1.5×104 A. The lightning releases 3×108 J of energy and lasts for 2×10 -4 S What Is the average electromotive force (e.m.f) between the cloud and the ground? a.4V b.100V c.1×108 V d.9×108 V 5 6