Current Electricity PYQs Set 10 (PDF)

Set 10 of 21 · Questions 271-300 of 612

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Mere Teacher · Previous Year Questions NEET Physics · Current Electricity · Set 10 (Q271-300)
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271. $In the circuit shown, the current through the 4 Ω resistor is 1 amp when the points P and M are connected to a d . c . voltage source. The potential difference between the points M and N is$ (1) $0.5 volt$ (2) $3.2 volt$ (3) $1.5 volt$ (4) $1.0 volt$ 272. $In the given part of a circuit, the potential at point B is zero. Then the potentials at A and C respectively are$ (1) $- 1.5 V, + 2 V$ (2) $+ 1.5 V, + 2 V$ (3) $+ 1.5 V, + 0.5 V$ (4) $+ 1.5 V, - . 0.5 V$ 273. $In a metre-bridge when a resistance in the left gap is 2Ω and unknown resistance in the right gap, the balance length is found to be 40 cm . On shunting the unknown resistance with 2Ω, the balance length changes by:$ (1) $22.5 cm$ (2) $20 cm$ (3) $62.5 cm$ (4) $65 cm$ 274. $In the given figure R_{1} = 10Ω, R_{2} = 8Ω, R_{3} = 4Ω and R_{4} = 8Ω . Battery is ideal with emf 12 V . Equivalent resistant of the circuit and current supplied by battery are respectively:$ (1) $10.5Ω and 1.14 A$ (2) $12Ω and 1 A$ (3) $10.5Ω and 1 A$ (4) $12Ω and 11.4 A$ 275. $Kirchhoff’s first law, i . e . Σ i = 0 at a junction, deals with the conservation of$ (1) $momentum$ (2) $angular momentum$ (3) $charge$ (4) $energy$ 276. $In the figure shown, a circuit contains two identical resistors with resistance R = 5Ω and an inductance with L = 2 mH An ideal battery of 15 V is connected in the circuit. What will be the current through the battery long after the switch is closed?$ (1) $5.5 A$ (2) $7.5 A$ (3) $3 A$ (4) $6 A$ 277. $A potential divider circuit is shown in figure. The output voltage V_{0} is$ (1) $4 V$ (2) $2 mV$ (3) $0.5 V$ (4) $12 mV$ 278. $If the Wheatstone's bridge with four resistors R_{1}, R_{2} and R_{3}, R_{4} is balanced, then the correct expression is$ (1) $\frac{R _{2}}{R _{1}} = \frac{R _{4}}{R _{3}}$ (2) $\frac{R _{2}}{R _{3}} = \frac{R _{1}}{R _{4}}$ (3) $R_{1} R_{2} = R_{3} R_{4}$ (4) $R_{1} + R_{2} = R_{3} + R_{4}$ 279. $Cell having an emf ε and internal resistance r is connected across a variable external resistance R .As the resistance R is increased, the plot of potential difference V across R is given by:$ (1) (2) (3) (4) 280. $The value of current through the 5Ω resistor of the given circuit is$ (1) $\frac{1}{25} A$ (2) $\frac{2}{25} A$ (3) $\frac{2}{23} A$ (4) $\frac{1}{23} A$ 281. $I - V characteristic of a copper wire of length L and area of cross-section A is shown in figure. The slope of the curve becomes$ (1) $less if the area of the wire is increased$ (2) $less if the length of the wire is increased$ (3) $more if experiment is performed at higher temperature$ (4) $more if a wire of steel of same dimension is used.$ 282. $A potentiometer wire PQ of 1 m length is conneted to a standard cell E_{1} . Another cell E_{2} of emi 1.02 V is connected with a resistance ' r' and switch S (as shown in figure). With switch S open, the null position is obtained at a distance of 49 cm from Q . The potential gradient in the potentiometer wire is$ (1) $0.03 V / cm$ (2) $0.02 V / cm$ (3) $0, 01 V / cm$ (4) $0.04 V / cm$ 283. $In the circuit shown, if a conducting wire is connected between points A and B, the current in this wire will$ (1) $flow from B to A$ (2) $flow from A to B$ (3) $flow in the direction which will be decided by the value of V$ (4) $be zero.$ 284. $In the circuit shown below, the ammeter and the voltmeter readings are 3 A and 6 V respectively. Then the value of the resistance R is$ (1) $> 2Ω$ (2) $\geq2Ω$ (3) $2Ω$ (4) $< 2Ω$ 285. $For the circuit shown, with R_{1} = 1.0Ω, R_{2} = 2.0Ω, E_{1} = 2 V and E_{2} = E_{3} = 4 V, the potential difference between the points a' and 'b' is approximately (in V):$ (1) $2.7$ (2) $2.3$ (3) $3.7$ (4) $3.3$ 286. $In the experimental set up of meter bridge shown in the figure, the null point is obtained data distance of 40 cm fromA. If a 10Ω resistor is connected in series with R_{1}, the null point shifts by 10 cm . The resistance that should beconnected in parallel with (R_{1} + 10) Ω such that the null point shifts back to its initial position is :$ (1) $20Ω$ (2) $40Ω$ (3) $60Ω$ (4) $30Ω$ 287. $The ratio of heat dissipated per second through the resistance 5Ω and 10Ω in the circuit given below is:$ (1) $1 : 2$ (2) $2 : 1$ (3) $4 : 1$ (4) $1 : 1$ 288. $The equivalent resistance between A and B in the given circuit will be$ (1) $R$ (2) $2R$ (3) $\frac{R}{2}$ (4) $6R$ 289. $A meter bridge with two resistances R_{1} and R_{2} as shown in figure was balanced (null point) at 40 cm from the point P . The null point changed to 50 cm from the point P, when 16Ω resistance is connected in parallel to R_{2} . The values of resistances R_{1} and R_{2} are____$ (1) $R_{2} = 4Ω, R_{1} = \frac{4}{3} Ω$ (2) $R_{2} = 16Ω, R_{1} = \frac{16}{3} Ω$ (3) $R_{2} = 12Ω, R_{1} = \frac{12}{3} Ω$ (4) $R_{2} = 8Ω, R_{1} = \frac{16}{3} Ω$ 290. $Two metal wires of identical dimensions are connected in series. If σ_{1} and σ_{2} are the conductivities of the metal wires respectively, the effective conductivity of the combination is$ (1) $\frac{σ _{1} + σ _{2}}{σ _{1} σ _{2}}$ (2) $\frac{σ _{1} σ _{2}}{σ _{1} + σ _{2}}$ (3) $\frac{2 σ _{1} σ _{2}}{σ _{1} + σ _{2}}$ (4) $\frac{σ _{1} + σ _{2}}{2 σ _{1} σ _{2}}$ 291. $A uniform metallic wire has a resistance of 18 Ω and is bent into an equilateral triangle. Then, the resistance between any two vertices of the triangle is:$ (1) $4$ (2) $12$ (3) $2$ (4) $8$ 292. $As shown in the figure, in a Wheatstone's bridge, three resistances P, Q and R are connected in the three arms and the fourth arm is formed by two resistances S_{1} and S_{2} connected in parallel. The condition for the bridge to be balanced is$ (1) $\frac{P}{Q} = \frac{2 R}{S _{1} + S _{2}}$ (2) $\frac{P}{Q} = \frac{R ( S _{1} + S _{2} )}{S _{1} S _{2}}$ (3) $\frac{P}{Q} = \frac{R ( S _{1} + S _{2} )}{2 S _{1} S _{2}}$ (4) $\frac{P}{Q} = \frac{R}{S _{1} + S _{2}}$ 293. $A cell E_{1} of emf 6V and internal resistance 2Ω is connected with another cell E_{2} of emf 4V and internal resistance 8Ω (as shown in the figure). The potential difference across points X and Y is:$ (1) $3.6 V$ (2) $10.0 V$ (3) $5.6 V$ (4) $2.0 V$ 294. $Five identical resistors each of resistance R = 1500Ω are connected to a 300 V battery as shown in the circuit. The reading of the ideal ammeter A is$ (1) $\frac{1}{5} A$ (2) $\frac{3}{5} A$ (3) $\frac{2}{5} A$ (4) $\frac{4}{5} A$ 295. $A current of 3 amp. flows through the 2Ω resistor shown in the circuit. The power dissipated in the 5Ω resistor is$ (1) $1 watt$ (2) $5 watt$ (3) $4 watt$ (4) $2 watt$ 296. $The value of unknown resistance (x) for which the potential difference between B and D will be zero in the arrangement shown, is:$ (1) $3Ω$ (2) $42Ω$ (3) $9Ω$ (4) $6Ω$ 297. $What is the current through the battery in the circuit shown below$ (1) $1.5 A$ (2) $0.5 A$ (3) $0.25 A$ (4) $1.0 A$ 298. $The meter bridge shown in the balance position with \frac{P}{Q} = \frac{l _{1}}{l _{2}} . If we now interchange the positions of galvanometer and cell, will the bridge work? If yes, what will be balanced condition? [NEET 2019]$ (1) $Yes, \frac{P}{Q} = \frac{l _{2} - l _{1}}{l _{2} + l _{1}}$ (2) $No, no null point$ (3) $Yes, \frac{P}{Q} = \frac{l _{2}}{l _{1}}$ (4) $Yes, \frac{P}{Q} = \frac{l _{1}}{l _{2}}$ 299. $n identical resistance are taken in which \frac{n}{2} resistors are joined in series in the left gap and the remaining \frac{n}{2} resistances are joined in parallel in the right gap of a metre bridge. Balancing length in cm is.$ (1) $100 \cdot \frac{n ^{2}}{n ^{2} + 4}$ (2) $100 \cdot \frac{n ^{2}}{n ^{2} + 1}$ (3) $400 \cdot \frac{1}{n ^{2} + 4}$ (4) $400 \cdot \frac{1}{n ^{2} + 1}$ 300. $The resistances in the two arms of the meter bridge are 5 Ω and RΩ respectively When the resistance R is shunted with an equal resistance, the new balance point is at 1.6 l_{1} . The resistance R is$ (1) $10 Ω$ (2) $15 Ω$ (3) $20 Ω$ (4) $25 Ω$