Current Electricity Questions and Answers

lectricity charge on capacitor is t Zero Consider the circuit shown R is a variable resistance e is some unknown emf with polarity as shown Match the following B 202 6 V C 402 Column l A Current passing through 4 2 resistance can be zero B Current passing through 4 2 resistance can be from F to C direction C Current passing through 2 2 resistance will be from B to A direction D Current passing through resistance R will be from E to D direction p q R E 1 Column II Possible if e 6 Possible if e 6 r Possible if e 6 s Possible for any value of e Possible for any value of resistance R

Give an example of appliances at home that is connected using a series connection Draw the circuit in a series connection

4 2 A long horizontal wire AB which is free to move in a vertical plane and carries a steady current of 20A is in equilibrium at a height of 0 01m over another parallel long wire CD which is fixed in a horizontal plane and carries a steady current of 30A as shown in figure 4 248 Show that when AB is slightly depressed it executes simple harmonic motion Find the period of oscillations i 20A B

ALLEN A thick wire of resistance 2502 is drawn into a 26 thin wire such that its length becomes four times The new resistance of the wire will be 1 500 2 250 3 100 22 4 4000 2502 fara a anten ar fare ar fad and not at at ei an 1 500 2 250 3 100 2 4 4000

3 0 5 02 10V 4 0 72 10V When a resistance of 2 ohm is connected across 36 the terminals of a cell the current is 0 5A When the resistance is increased to 5 ohm the current is 0 25 A The emf of the cell is 1 1 0 V 2 1 5V 3 2 0 V 4 2 5V 3 0 52 10V 2 2 0 2 02 5V 4 0 7 02 10V 0 25 fara 1 1 0 V 2 1 5V 3 2 0 V 4 2 5V

The switch shown in the figure has been opened for long time and closes at t 0 Find V t for all t 8A 1 VR 10Q2 X t 0 2092 1 F 2002

given We have to find the total resistance of i t The answer to this is that in this circuit short circuit will happen please give a detailed solution of this q uestion This question is of higher level than cla ss10 Voltage of bathry is a Nett R 22 WM R 1222 Rg d R 222 R R 108 10

Circuit diagram of metre bridge is shown in figure The null point is found at a distance of 40 cm from A If now a resistance of 120 is connected in parallel with S the null point occurs at 64 cm Determine the value of R and S R S B AG A metaller ale mal matemala un buralaukurall X Question Type Single Correct Type

The current I through the 4ohm resistor in the network sh own in figure is The current I through the 40 resistor in the network shown in figure is S W 5 100 to A ONE 1 2 A 3 2 5 A 10V 29 ww 10V 20 www 452 I B 2 4A 4 1 25 A 2 31 5 4 2x2

In the metre bridge experiment resistances are 39 27 g v f u fara connected as shown in the following figure The balancing length is 55 cm Now an unknown resistance x is connected in series with P and the new balancing length is found to be 75 cm The value of x is P30 54 1 2 13 100 48 B 2 20 3 DER TEST SERIES JOINT PACKAGE COURSE 4 48 1 X 5 P 75 x P 30 100 2 3 48 B 11 48 0999DMD310320002 4

214 Electrons in a conductor are moving randomely due to thermal energy this making it s average velocity zerc and thus displacement On applying external electrical field they start moving with drift velocity i Obtain relation for drift velocity on the basis of given information ii From the result of drift velocity define relaxation time 3 1

When 2000 ohm load is connected across a 20 mA current source it is fou that18 mA flows in the load What is the internal resistance of the source O 3000 ohm O 6000 ohm O 12000 ohm O18000 ohm

In the circuit shown in figure Select the correct option s A current passing through 2 2 resistance is zero B current passing through 4 2 resistance is 5 A C current passing through 5 2 resistance is 4 A D all of the above ww 40 202 www 20V www 542

Potential difference across the terminals of a non ideal battery is A zero when it is short circuited B less than its emf when current flows from negative terminal to positive terminal inside the battery C zero when no current is drawn from the battery D greater than its emf when current flows from positive terminal to negative terminal inside the

The potential drop across the 302 resistor is 30 1 IV 3 2 V 402 3V 602 2 1 5 V 4 3 V USR ER TEST SERIES JOINT PACKAGE COURSE Page 8 44 29 1 4R 1 IV 3 2 V 2 2R 3 R 4 0 5R fada funda fare Space for Rough Work day ITE 607 3V 2 15 V 4 3 V 09990MD310320002 NEET UG 2021 19072020

A battery of emf E and internal resistance r is connected across a resistance R Resistance R can be adjusted to any value greater than or equal to zero A graph is plotted between the current passing through the resistance i and potential difference V across it Select the correct alternative s A Internal resistance of the battery is 50 B Emf of the battery is 10 V C Maximum current which can be taken from the battery is 2 A D V I graph can never be a straight line as shown in figure Volt 10 amper

Three resistors are in parallel The current in the first resistor is 0 5 A The power dissipated in the second is 15 watts The voltage across the third is 200 volts Determine total resistance of circuit if total current is 1 A O 100 ohm O 200 ohm 300 ohm 400 ohm

Resistance of a wire at temperature t C is R Ro 1 at bt Here R is the temperature at 0 C The temperature coefficient of resistance at temperature tis a 2bt A B a 2bt C 1 at bt D constant 1 at bt a 2bt

A wire of length 100cm carries a steady current i The potentials at the ends of the wire is 5V and 25V The value of potential at x 30cm is A 6 5 V 5 x 130 cm B 11 V 25 100 cm C 3 5 V D 4 V

In the circuit shown P R the reading of the galvanometer is same with switch S open or closed Then 1 R IR IG S ww H a Question Type Single Correct Type G

Under what conditions current passing through the resistance R can be increased by short circuiting the battery of emf E The internal resistances of the two batteries are r and r respectively A E r E R C E E E R B E E R r D E r E R r E 12

8 Given C 2uF C2 4 F C3 8 F C C2 C3 are initially uncharged Initially all the keys are open Then 6h www 12 V 3h 12 h www Tim k C A In steady state after closing k alone the charge in capacitor C is zero B In steady state after closing ki alone the charge in capacitor C and C3 are 8 C and 4 C C In steady state after closing ki alone the current drawn from the cell is 2A D In steady state after closing k and k the current drawn from the cell is 1A

30 ALLEN The equivalent resistance between the points A 30 fefe for in and B in the following circuit is www 1 3 120 3 6 240 50 B www www 150 2 1 560 4 12 480 B 1 3 120 3 6 2402 www www www 50 www SO 2 1 560 4 12 480

A constant potential difference is maintained between the ends of a conductor having non uniform cross section Which of the following quantities will not change along the length of the conductor drift speed b electric field c resistance d current

In the figure the value of resistors to be connected between C and D so that the resistance of the entire circuit between A and B does not change with the number of elementary sets used is A Be R 1 R R R ww ww 3 3 R ww R 2 R 3 1 RE R ww R R R R ww ww R D

Phy Section This section contains 15 SINGLE CORRECT TYPE questions Out of these 15 questions candidate can choose to attempt any 10 Two spheres A and B of exactly same initial mass are given equal positive and negative charges respectively Their masses after charging Remains unaffected Read More O Mass of A mass of B Mass of A mass of B Nothing can be said

A conducting frame is placed in a horizontal plane as shown in the figure The two sides are parallel and separated by a distance of 0 25 m A massless conducting rod can slide without friction on the frame The total resistance of the circuit is 40 Q The rod is connected to a 0 2 kg mass by a massless cord which passes over a massless and frictionless pulley uniform A magnetic field of 2 T points vertically upward The voltage of the battery is 100 V Find the constant velocity in m s with which the rod and mass eventually move 40 2 100 V B 2T 0 2 kg 0 25 m

When two charged particles are placed at the certain distance apart in vacuum then the force experienced by one of the charges is equal to F If vacuum is replaced by a medium of dielectric constant 6 then the net force experienced by the charged particle will be equal to

A battery of e m f E and internal resistance ris connected to a variable resistor R as shown in figure Which of the following is true E R wwwwwwww www

If R in Figure 5 25 is open the base voltage is a 10 V b 0 V c 3 13 V d 0 7 V If R is open the collector current in Figure 5 25 is a 5 17 mA b 10 mA c 4 83 mA R 10 k R 4 7 k Vcc 10 V Re 1 0 k a Faulty circuit 470 0 FIGURE 5 25 10 0v d 0 mA

In which of the following circuit is the current maximum just after the switch S is closed i iii E E El R www A i LOGO sv S R S L 000000 R R L R L eeeeee 000000 B ii D Both ii and iii

Phy Section This section contains 35 SINGLE CORRECT TYPE questions Each question has 4 choices 1 2 3 and 4 C When a potential difference Vis applied across a conductor of length the drift speed of electrons is Proportional to V Proportional to Independent of V Proportional to

20 180 There is a wire of resistance 440 Q The wire can bear a maximum current of 2 A The wire is to be cut into n number of identical pieces and then connected suitably across 220 V supply sc as to dissipate maximum power The value of n is X2 3

76 The resistivity of a potentiometer wire is if the area of cross section of the wire is 4cm the current flowing in the circuit is 1A the potential gradient is 7 5 v m 1 3 x 10 22 m 3 4 x 10 222 m 2 2x 10 22 m 4 5 x 10 22 m

100 2002 2002 4092 and 5092 are connected as shown in figure The equivalent resistance between points A and B is C 10 2 A www 20 2 209 50 2 B 40 9 53 D 10 109 a 40 b 60 2 c 2002 d 30 2

Will power not depend on the res stance of apparatus 27 An apparatus is connected to an ideal battery as shown in figure For what value of current power delivered to the apparatus will be maximum R 1 2 E 2R E 4R apparatus E 3 4 information is insufficient 25

Same mass of copper is drawn into two wires of radius 1 mm and 3 mm Two wires are then connected in series and current is passed through them Heat produced in the wires is in ratio of 3 1 9 1 81 1

5 n identical cells are joined correctly in series with another two cells A and B with reverse polarities Emf of each cell is E and internal resistance is r Potential difference across cell A is n 4 2E 1 25 n 1 1 1 2 2E 1

An external resistance R is connected across a battery of e m f E and internal resistance r Determine the condition for which the production of heat in R will be maximum A galvanometer of resistance 45 ohm shunted with a resistance of 5 ohm is joined in series with a resistance of 84 ohm and a battery of e m f 4 5 volt having internal resistance 1 5 ohm Find the current passing through a the battery b the galvanometer and c the shunt 2 3

Electrical Energy Power Potential Difference 10 In the circuit shown the thermal power dissipated in R is P The thermal power dissipated in R is R R 1 P 3 2 P 3 L www R R R 2R 2 4P 9 10

A body cools from a temperature 3T to 2T in 10 minutes The room temperature is T Assume that Newton s law of cooling is applicable The temperature of the body at the end of next 10 minutes will be NEET II 2016 4 T 3 T Correct

20 In potentiometer wire of length L and resistance 10 2 is connected in series with a battery of emf 2 5 V and a resistance in its primary circuit The null point corresponding to a cell of a emf 1 V is obtained at a distance If the resistance in the primary circuit is doubled then the position of new null point will be 1 0 6L 2 0 8L 3 4L 4 0 5L

All capacitors were initially uncharged 10 F 1502 1002 www 50V 1502 S F HE A Battery current just after closing of switch S is 3 42 A B Battery current just after closing of switch S is 0 962 A C Battery current after long time of closing of switch S is 3 42 A D Battery current after long time of closing of switch S is 0 962 A

The current i at time t 0 and t respectively for the given circuit is B 18E 55 5E 18 5E 18E 18 55 5E 10E 18 33 10 5E 50 10 Ai 50 E 402 mooooo L

galvanometer Now the first battery E is replaced by second battery E for working by making K open and K closed The galvanometer gives the null deflection at J The value of is E where a E2 wwwwww Rh K E B 3 E 20 cm J m K J 60 cm Answer K

21 If equivalent resistance between points A and X is 5 92 and equivalent resistance between A and B is 10 2 then find R A 100 B 1 222 2 59 3 39 X 4 100 sch www R R 2 V 2 V X 39 3 R R R 3 4 R R 10 R 95

One of the circuits for the measurement of resistance by potentiometer is shown The galvanometer is connected at point A and zero deflection is observed at length PJ 30 cm In second case the secondary cell is changed Take Es 10 V and r 10 in 1st reading and Es 5V and r 20 in 2nd reading In second case the zero deflection is observed at length PJ 10 cm What is the resistance R in ohm Ep P R wwww www J A

each of resistance R A battery of negligible internal resistance is connected across the opposite corners A and C of the top face of the cube A current I enters the corner A and leaves the corner C The current passing through the resistor BF is B A zero B C D A B 9 O 3 5R 6 3R 4 E 5R 12 3R www www ww www The effective resistance between the points A and C in the above circuit is www ww H 10 mu ww

If the mean free path of a gas is at one atmospheric pressure then its value at 5 atmospheric pressure will be temperature is assumed to be constant 1 X 3 A 2 5 5 4

37 A millivoltmeter of 25 millivolt range is to be converted into an ammeter of 25 ampere range The value in ohm of necessary shunt will be 1 1 3 0 001 AIPMT Prelims 20121 2 0 05 4 0 01