Current Electricity PYQs Set 16 (PDF)

Set 16 of 25 · Questions 451-480 of 723

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Mere Teacher · Previous Year Questions JEE Main Physics · Current Electricity · Set 16 (Q451-480)
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451. $Five equal resistances are connected in a network as shown in figure. The net resistance between the points A and B is:$ (1) $\frac{3 R}{2}$ (2) $\frac{R}{2}$ (3) $R$ (4) $2R$ 452. $The four arms of a Wheatstone bridge have resistances as shown in the figure. A galvanometer of 15Ω resistance is connected across BD . Calculate the current through the galvanometer when a potential difference of 10 V is maintainedacross AC .$ (1) $2.44 μA$ (2) $2.44 mA$ (3) $4.87 mA$ (4) $4.87 μA$ 453. $A conducting wire of length 'l', area of cross-section A and electric resistivity ρ is connected between theterminals of a battery. A potential difference V is developed between its ends, causing an electric current. If the length of the wire of the same material is doubled and the area of cross-section is halved, the resultantcurrent would be:$ (1) $\frac{1}{4} \frac{VA}{ρl}$ (2) $\frac{3}{4} \frac{VA}{ρl}$ (3) $\frac{1}{4} \frac{ρl}{VA}$ (4) $4 \frac{VA}{ρl}$ 454. $In an ammeter, 5 % of the main current passes through the galvanometer. If resistance of the galvanometer is G, the resistance of ammeter will be:$ (1) $\frac{G}{20}$ (2) $\frac{G}{199}$ (3) $199 G$ (4) $200 G$ 455. $In the Wheatstone's network given, P = 10Ω, Q = 20Ω, R = 15Ω, S = 30Ω . The current passing through the battery (of negligible internal resistance) is$ (1) $0.36 A$ (2) $0$ (3) $0.18 A$ (4) $0.72 A$ 456. $A capacitor of 8 F is connected as shown. Charge on the plates of the capacitor$ (1) $32 C$ (2) $40 C$ (3) $0 C$ (4) $80 C$ 457. $For the network shown in the figure the value of the current i is$ (1) $\frac{9 V}{35}$ (2) $\frac{18 V}{5}$ (3) $\frac{5 V}{9}$ (4) $\frac{5 V}{18}$ 458. $Three resistors having resistances r_{1}, r_{2} and r_{3} are connected as shown in the given circuit. The ratio i_{3} / i_{1} of currents in terms of resistances used in the circuit is [NEET 2021]$ (1) $\frac{r _{1}}{r _{2} + r _{3}}$ (2) $\frac{r _{2}}{r _{2} + r _{3}}$ (3) $\frac{r _{1}}{r _{1} + r _{2}}$ (4) $\frac{r _{2}}{r _{1} + r _{3}}$ 459. $The Wheatstone bridge shown in the diagram is balanced. If P_{3} is the power dissipated by R_{3} and P_{1} is the power dissipated by R_{1}, then the ratio \frac{P _{3}}{P _{1}} is$ (1) $\frac{K}{L}$ (2) $\frac{K ^{2}}{L}$ (3) $\frac{L}{K ^{2}}$ (4) $\frac{L}{K}$ 460. $A student measures the terminal potential difference (V) of a cell (of emf ϵ and internal resistance r) as a function of the current (I) flowing through it. The slope, and intercept, of the graph between V and I, then, respectively, equal$ (1) $- r and ϵ$ (2) $r and - ϵ$ (3) $- ϵ and r$ (4) $ϵ and - r$ 461. $In the given circuit, an ideal voltmeter connected across the 10Ω resistance reads 2 V . The internal resistance r, of each cell is$ (1) $1Ω$ (2) $0.5Ω$ (3) $1.5Ω$ (4) $0Ω$ 462. $In this figure the resistance of the coil of galvanometer G is 2 Ω . The emf of the cell is 4 V. The ratio of potential difference across C_{1} and C_{2} is$ (1) $1$ (2) $\frac{4}{5}$ (3) $\frac{5}{4}$ (4) $\frac{3}{4}$ 463. $In the given figure, there is a circuit of potentiometer of length AB = 10m. The resistance per unit length is 0.1Ω per cm. Across AB, battery of emf E and internal resistance 'r' is connected. The maximum value of emf measured by this potentiometer is:$ (1) $5V$ (2) $2.25V$ (3) $6V$ (4) $2.75V$ 464. $For the resistance network shown in the figure, choose the correct option(s).$ (1) $The current through PQ is zero.$ (2) $I_{1} = 3 A.$ (3) $The potential at S is less than that at Q.$ (4) $I_{2} = 2 A.$ 465. $In the given circuit the internal resistance of the 18 V cell is negligible. If R_{1} = 400Ω, R_{3} = 100Ω and R_{4} = 500Ω and the reading of an ideal voltmeter across R_{4} is 5 V, then the value of R_{2} will be:$ (1) $300Ω$ (2) $450Ω$ (3) $550Ω$ (4) $230Ω$ 466. $In the given circuit, the current I through the battery will be$ (1) $2 5 A$ (2) $1A$ (3) $2 A$ (4) $1.5 A$ 467. $In a meter bridge experiment, the circuit diagram and the corresponding observation table are shown in figure. SI. NO. R 1 (cm) 1100060210013310 1.5 41 1.0 Which of the reading is consistent?$ (1) $3$ (2) $2$ (3) $4$ (4) $1$ 468. $When the switch S, in the circuit shown, is closed then the valued of current i will be:$ (1) $3 A$ (2) $5 A$ (3) $4 A$ (4) $2 A$ 469. $Each resistance in the given cubical network has resistance of 1Ω and equivalent resistance between A and B is$ (1) $\frac{5}{12} Ω$ (2) $\frac{12}{5} Ω$ (3) $\frac{5}{6} Ω$ (4) $\frac{6}{5} Ω$ 470. $A potentiometer wire of length 200 cm has a resistance of 20Ω . It is connected in series with a resistance of 10Ω and an accumulator of emf 6 V having negligible internal resistance. A source of 2.4 V is. balanced against a length L of the potentiometer wire. The value of L is$ (1) $100 cm$ (2) $120 cm$ (3) $110 cm$ (4) $140 cm .$ 471. $Two electric bulbs marked 25W - 220V and 100W - 220 V are connected in series to a 440 V supply. Which of the bulbs will fuse?$ (1) $both$ (2) $100W$ (3) $25W$ (4) $neither$ 472. $In a Wheatstone bridge (see fig.), Resistances P and Q are approximately equal. When R = 400Ω, the bridge is balanced. On interchanging P and Q, the value of R, for balance, is 405Ω . The value of X is close to:$ (1) $401.5 ohm$ (2) $404.5 ohm$ (3) $403.5 ohm$ (4) $402.5 ohm$ 473. $In the given electrical circuit, which one of the following equation is a correct equation?$ (1) $E_{2} - i_{2} r_{2} - E_{1} - i_{1} r_{1} = 0$ (2) $E_{1} - (i_{1} + i_{2}) R + i_{1} r_{1} = 0$ (3) $E_{1} - (i_{1} + i_{2}) R - i_{1} r_{1} = 0$ (4) $- E_{2} - (i_{1} + i_{2}) R + i_{2} r_{2} = 0$ 474. $In the given figure, a battery of emf E is connected across a conductor PQ of length ' l' and different area of cross-sections having radii r_{1} and r_{2} (r_{2} < r_{1}) Choose the correct option as one moves from P to Q:$ (1) $Drift velocity of electron increases.$ (2) $Electric field decreases.$ (3) $Electron current decreases.$ (4) $All of these$ 475. $In the given circuit, the current in resistance R_{3} is:$ (1) $1 A$ (2) $1.5 A$ (3) $2 A$ (4) $2.5 A$ 476. $In the circuit given below, if the bulb is to glow with maximum intensity, the value of ' R' is (neglect internal resistance of the cell)$ (1) $1.25Ω$ (2) $4.5Ω$ (3) $6Ω$ (4) $8.5Ω$ 477. $In meter bridge experiment for measuring unknown resistance 'S', the null point is obtained at a distance 30 cm from the left side as shown at point D. If R is 5.6k Ω, then the value of unknown resistance 'S' will be ______Ω .$ 478. $10 resistors each of resistance 10 Ω can be connected in such as to get maximum and minimum equivalent resistance. The ratio of maximum and minimum equivalent resistance will be________.$ 479. $A potentiometer wire of length 10m and resistance 20 Ω is connected in series with a 25 V battery and an external resistance 30 Ω . A cell of emf E in secondary circuit is balanced by 250 cm long potentiometer wire. The value of E (in volt) is x/10. The value of x is_______.$ 480. $In the experiment to determine the galvanometer resistance by half-deflection method, the plot of 1/ θ vs the resistance (R) of the resistance box is shown in the figure. The figure of merit of the galvanometer is ______\times 10^{- 1} A / division. [The source has emf 2 V]$