Current Electricity PYQs Set 19 (PDF)

Set 19 of 21 · Questions 541-570 of 612

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Mere Teacher · Previous Year Questions NEET Physics · Current Electricity · Set 19 (Q541-570)
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541. $Five current carrying conductors meet at a point P. What is the magnitude and direction of the current in the fifth conductor?$ (1) $1 A from Q to P$ (2) $1 A from P to Q$ (3) $3 A from P to Q$ (4) $2 A from Q to P$ 542. $A Copper (Cu) rod of length 25cm and cross-sectional area 3 m m^{2} is joined with a similar Aluminium (Al) rod as shown in figure. Find the resistance of the combination between the ends A and B. (Take Resistivity of Copper = 1.7 \times 1 0^{- 8} ΩM Resistivity of Aluminium = 2.6 \times 1 0^{- 8} Ωm)$ (1) $2.170 m Ω$ (2) $1.420 m Ω$ (3) $0.0858 m Ω$ (4) $0.858 m Ω$ 543. $In the given figure, the emf of the cell is 2.2V and if internal resistance is 0.6Ω . Calculate the power dissipated in the whole circuit:$ (1) $1.32W$ (2) $0.65W$ (3) $2.2W$ (4) $4.4W$ 544. $The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10Ω is:$ (1) $0.5$ (2) $0.8$ (3) $1.0$ (4) $0.2$ 545. $Find the mobility of electron in a wire, if its average collision time is 9.1 \times 1 0^{- 15} s . (charge of electron = 1.6 \times 1 0^{- 19} C and mass of electron (= 9.1 \times 1 0^{- 31} kg)$ (1) $9.1\times 1 0^{- 3} m2/V-s$ (2) $1.6 \times 10^{- 3} m^{2} / V - s$ (3) $1.75 \times 10^{- 3} m^{2} / V - s$ (4) $1 \times 10^{- 3} m^{2} / V - s$ 546. $Find the resistance of a cube of edge 60 cm, made of a material of specific resistance 60 \times 10^{- 8} Ωm .$ (1) $2.5 \times 1 0^{- 5} Ω$ (2) $1 0^{- 8} Ω$ (3) $1 0^{- 6} Ω$ (4) $5 \times 1 0^{- 4} Ω$ 547. $A current of 2 A, passing through a conductor produces 80 J of heat in 10 seconds. The resistance of the conductor in ohm is$ (1) $0.5$ (2) $2$ (3) $4$ (4) $20$ 548. $In a meter bridge experiment null point is obtained at l cm from the left end. If the meter bridge wire is replaced by a wire of same material but twice the area of cross-section, then the null point is obtained at a distance$ (1) $2 l cm from left end$ (2) $l cm from left end$ (3) $\frac{l}{2} cm from left end$ (4) $\frac{l}{4} cm from left end$ 549. $A uniform metallic wire carries a current 2 A. when 3.4 V battery is connected across it. The mass of uniform metallic wire is 8.92 \times 1 0^{- 3} kg. density is 8.92 \times 1 0^{3} kg/ m^{3} and resistivity is 1.7 \times 1 0^{- 8} Ω -m. The length of wire is:$ (1) $l =6.8m$ (2) $l =10m$ (3) $l = 5m$ (4) $l =100m$ 550. $A cell can be balanced against 100 cm and 110 cm of potentiometer wire, respectively with and without being short circuited through a resistance of 10 Ω . Its internal resistance is$ (1) $2.0 ohm$ (2) $zero$ (3) $1.0 ohm$ (4) $0.5 ohm$ 551. $The quantities that don't change when a resistor connected to a battery is heated due to the current are (A) drift speed (B) resistivity (C) Resistance (D) Number of free electrons$ (1) $B and C$ (2) $D$ (3) $A$ (4) $A and D$ 552. $(A) The drift velocity of electrons decreases with the increase in the temperature of conductor. (B) The drift velocity is inversely proportional to the area of cross-section of given conductor. (C) The drift velocity does not depend on the applied potential difference to the conductor. (D) The drift velocity of electron is inversely proportional to the length of the conductor. (E) The drift velocity increases with the increase in the temperature of conductor. Choose the correct answer from the options given below:$ (1) $A and B only$ (2) $A and D only$ (3) $B and E only$ (4) $B and C only$ 553. $Wire bound resistors are made by$ (1) $winding the wires of an alloy of Ge, Au, Ga$ (2) $winding the wires of an alloy of Cu, Al, Ag$ (3) $winding the wires of an alloy of manganic, constantan, nichrome$ (4) $winding the wires of an alloy of Si, Tu, Fe$ 554. $A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance R, connected across the given cell, has values of (i) infinity (ii) 9.5 Ω the balancing lengths on the potentiometer wire are found to be 3 m and 2.85 m, respectively The value of internal resistance of the cell is$ (1) $0.25 Ω$ (2) $0.95 Ω$ (3) $0.5 Ω$ (4) $0.75 Ω$ 555. $One kilowatt hour is equal to$ (1) $36 \times 1 0^{- 5} J$ (2) $36 \times 1 0^{- 4} J$ (3) $36 \times 1 0^{5} J$ (4) $36 \times 1 0^{3} J$ 556. $Consider an electrical conductor connected across a potential difference V. Let Δ q be a small charge moving through it in time Δ t . If I is the electric current through it, (i) the kinetic energy of the charge increases by IV Δ t . (ii) the electric potential energy of the charge decreases by IV Δ t . (iii) the thermal energy of the conductor increases by IV Δ t . Then the correct statement/s is/are$ (1) $(i)$ (2) $(i) and (ii)$ (3) $(i) and (iii)$ (4) $(ii) and (iii)$ 557. $A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance, R, connected across the given cell, has values of. (i) infinity (ii) 9.5Ω The 'balancing lengths, on the potentiometer wire are found to be 3m and 2.85 m, respectively. The value of internal resistance of the cell is:$ (1) $0.25$ (2) $0.95$ (3) $0.5$ (4) $0.75$ 558. $Ohm's law is applicable to$ (1) $diode$ (2) $transistor$ (3) $electrolyte$ (4) $conductor$ 559. $Statement (I): Specific resistance depends on nature of material and independent of temperature of the material. Statement (II): A wire of resistance 6Ω is drawn out so that its new length is four times its original length. The resistance of the new wire is 48Ω . Statement (III): Drift velocity is the average constant velocity acquired by free electrons inside a metal by the application of an electric field which results in current. Which of the following is correct?$ (1) $Statements I, II and III are true$ (2) $Statement I is true, but statements II, III is false$ (3) $Statement III is true, but statements I, II are false$ (4) $Statements II, III are true, but statement I is false$ 560. $A potentiometer wire of length L and a resistance r are connected in series with a battery of e.m.f. E_{0} and a resistance r_{1} . An unknown e.m.f. E is balanced at a length l of the potentiometer wire. The e.m.f. E will be given by$ (1) $\frac{E _{0} l}{L}$ (2) $\frac{L E _{0} r}{( r + r _{1} ) l}$ (3) $\frac{L E _{0} r}{l r _{1}}$ (4) $\frac{E _{0} r}{( r + r _{1} )} \frac{l}{L}$ 561. $The length of a potentiometer wire is 1200 cm and it carries a current of 60 mA . For a cell of emf 5 V and internal resistance of 20 Ω, the null point on it is found to be at 1000 cm . The resistance of whole wire is:$ (1) $80Ω$ (2) $100Ω$ (3) $120Ω$ (4) $60Ω$ 562. $A battery consists of a variable number n of identical cells (having internal resistance r each) which are connected in series. The terminals of the battery are short-circuited and the current I is measured. Which of the graphs shows the correct relationship between I and n ?$ (1) (2) (3) (4) 563. $Model a torch battery of length l to be made up of a thin cylindrical bar of radius 'a' and a concentric thin cylindrical shell of radius 'b' filled in between with an electrolyte of resistivity ρ (see figure). If the battery is connected to a resistance of value R, the maximum Joule heating in R will take place for$ (1) $R = \frac{ρ}{π l} ln (\frac{b}{a})$ (2) $R = \frac{2 ρ}{π l} ln (\frac{b}{a})$ (3) $R = \frac{ρ}{2 π l} ln (\frac{b}{a})$ (4) $R = \frac{ρ}{2 π} (\frac{b}{a})$ 564. $A circular wire has current density J = (2 \times 1 0^{10} \frac{A}{m ^{2}}) r^{2}, where r is the radial distance, out of the wire radius is 2 mm . The end-to-end potential applied to the wire is 50 V . How much energy (in joule) is converted to thermal energy in 100 s ?$ (1) $1200 π$ (2) $800 π$ (3) $3200 π$ (4) $600 π$ 565. $The current i in the network is:$ (1) $0.2 A$ (2) $0.3 A$ (3) $0 A$ (4) $0.6 A$ 566. $Which of the following resistivity (ρ) v / s temperature (T) curves is most suitable to be used in wire bound standard resistors?$ (1) (2) (3) (4) 567. $The current flowing through R_{2} is:$ (1) $\frac{2}{3} A$ (2) $\frac{1}{2} A$ (3) $\frac{1}{3} A$ (4) $\frac{1}{4} A$ 568. $The drift velocity of electrons for a conductor connected in an electrical circuit is V_{d} . The conductor in now replaced by another conductor with same material and same length but double the area of cross section. The applied voltage remains same. The new drift velocity of electrons will be$ (1) $V_{d}$ (2) $\frac{V _{d}}{2}$ (3) $\frac{V _{d}}{4}$ (4) $2 V_{d}$ 569. $Given below are two statements: Statement I: A uniform wire of resistance 80 Ω is cut into four equal parts. These parts are now connected in parallel. The equivalent resistance of the combination will be 5 Ω . Statement II: Two resistance 2R and 3R are connected in parallel in a electric circuit. The value of thermal energy developed in 3R and 2R will be in the ratio 3:2. In the light of the above statements, choose the most appropriate answer from the options given below$ (1) $Both statement I and statement II are correct$ (2) $Both statement I and statement II are incorrect$ (3) $Statement I is correct but statement II is incorrect$ (4) $Statement I is incorrect but statement II is correct$ 570. $The current in the following circuit is$ (1) $2/3 A$ (2) $1 A$ (3) $1/8 A$ (4) $2/9 A .$