Current Electricity Questions and Answers

Q11 The virtual current in the a c circuit shown in Fig is 1 0 A Find virtual voltage across the coil L impedance of the circuit and reactance of the coil i ii iii L 000 1 0 A R www 120 V

A battery is used to charged a parallel plate capacitor after which it is disconnected Then the plates are pulled apart to twice their original separation This process will doubled the capacitance surface charge density on each plate stored energy electric field between the two places Marks 4 1

10A 11 a 8 18 b 9 18 c 10 18 d 8 8 www View Answer 13 in the circuit shown below 10V aes R3 Answer a Explanation For 2nd loop 10 2 12 13 3 12 0 For 3rd loop i3 2 3 2 10 As i solving above equations we get i 8 18A

In the figure 1 4 20 V 2 0 772 V R1 6 96 0 R2 2 60 0 R3 5 76 0 and both batteries are ideal What is the rate at which energy is dissipated in a R1 b R2 and c R3 What is the power of d battery 1 and e battery 2 R 18 R R E2

192 Awwwww B the equivalent resistance between A and B is 202 a 5 Q c 2 5 2 e 7 8 652 wwwwwww 122 2 52 FIGURE 3 9 26 252 402 www 40 b 822 d 6 8 2 Pb CET 2008 Kompl

What is the equivalent resistance of the following network of resistances 102 19 ww 1923 19 www 19 ww 12 MMM A

35 Each of the resistors shown in figure 32 E11 has a resistance of 10 Q2 and each of the batteries has an emf of 10 V Find the currents through the resistors a and b in the two circuits a b a a b

13 Current Electricity Set I 1 A current of 2A flows in a system of conductors shown in fig The potential difference V V will be A 2A D 252 352 B 352 G NEET AIIMS Sample Questions Physics Chemistry 252 1 1V 2 1V 3 2 V 4 2 V Two resistances R and R are joined as shown in the figure to two batteries of emf E and E If E is sho circuited the current through R is

5 3 In a step up transformer the turn ratio is 3 2 A battery of EMF 4 5V is connected across the primary windings of transformer The voltage developed in the secondary would be A 4 5V C 1 5V B 30 V Dy Zero

Hilt ww R R3 R ww www ww R4 R5 ww The figure shows a circuit consisting of a battery and five resistors with resistances and the battery emf listed below What is the potential difference across resi R R 7 00 0 R 12 00 R3 5 00 0 R4 13 00 R5 6 00 Q and V 27 0 V Potential difference across R

Consider the circuit shown in the figure Figure 1 Suppose the four resistors in this circuit have the values R 11 R 6 2 Rs 6 30 and R 122 and that the emf of the battery is E 18 V You may want to review Pages 748 751 Figure R R3 B ww 1 of 1 ww R R ww Part A Find the current through each resistor using the rules for series and parallel resist Express your answers using two significant figures separated by commas VAE Submit Previous Answers Request Answer Incorrect Try Again 14 attempts remaining Part B A Find the current through each resistor using Kirchhoff s rules Express your answers using two significant figures separated by commas VAX

cm and 3 cm Two wires of same length and thickness having specific resistances 6 respectively are connected in parallel The effective resistivity is p 2 cm The value of p to the nearest integer is en 1

Consider a 72 cm long wire AB as shown in the figure The galvanometer jockey is placed at P on AB at a distance x cm from A The galvanometer shows zero deflection A 12 02 www ven 54 er x C P 60 B The value of x to the nearest integer is

An ideal gas is expanding such that PT constant The coefficient of volume expansion of the gas is 1 7 7 7 du 3 vott 2 2 1 1 4 3 T T Pressure versus temperature graph of an ideal gas 4

In given network potential drop across A and B is V IR pres sent is same s drop by alb R 5x Rextend 18 2 1 Zoro 492 www 8 V A B www 42 42 8V 21 I V R P XXV P V R ev

A conductor of resistivity p and resistance R as shown in the figure is connected across a battery of e m f V Its radius varies from a at left end to b at right end The electric field at a point P at distance from left end of it is A B VI p TR Ia ba x 2VI p You Missed

Two cells of same emf E and internal resistance r are connected in parallel with a resistance of R To get maximum power in the external circuit the value of Ris E OR R O 2 R r R 2r R 4r r E T T R www

ii 20 V 202 www 2Q www ww 12 A B C 12 ww 5 V 12 wwwww 202 10 V 292 a Find the potential difference between the points A and B b Find current through 20 V cell if points A and B are connected

bulb and three identical resistors form a network as shown in diagram The applied potential such that the bulb is shining brightly A fourth identical resistor is added to the network such hat bulb becomes dark Where should this extra resistor be inserted A Between A D B Between D E C Between B D D Between C E B C wwwww Bulb E wwww F

The starter motor of a car engine draws a current of 200 A from the battery The copper wire to the motor is 5 70 mm in diameter and 1 2 m long The starter motor runs for 0 630 s until the car engine starts Part A How much charge passes through the starter motor Express your answer with the appropriate units HA Value Submit Units Request Answer ONC

3 The plot represents the flow of current through a wire for different time intervals The ratio of charges flowing through the wire corresponding to these time intervals is see figure 2 1 1 2 1 2 3 1 1 1 1 2 3 4 5678 Time in seconds 2 1 3 3 4 2 3 4

Magnitude of work done in moving 1 coulomb of charge from point A to point Bis 1 eit onder and far A farg Bars far fard A 5 A 3 J B5J 292 wwwww 392 5 A B

A charged particle has drift velocity of 7 5 10 4 m s and has mobility of 3 x 106 m V 1 s1 under the effect of electric field E The value of E is 2 25 x 10 10 V m O 3 10 V m 2 5 10 10 V m hr min 22x10 8 mm

When current comes out from positive terminal of battery energy is supplied by the battery to external circuit In this process e inside cell moves from higher potential to lower potential Work against the field inside the cell is done at the cost of chemical potential energy Net energy output from battery is also called work done by battery If AQ charge flows through battery then work done by battery is equal to AQ V where V is potential difference between two electrodes 1 F 1 F LYS 2 F 12 V 2 F Energy stored in capacitors is U when Sis open If Sis closed the charge passed through Sis Q

18 A prism is made of wire mesh with each side having equal resistance R A battery of 6 V and zero internal resistance is connected across E and F as shown in the figure The current in the branch AD if R is equal to 5 2 is FO D 1 0 6 A 121 08A www C A E eduty 4 www 2 0 4 A B TIL 6 V

23 A rigid insulated wire frame in the form of a rig gled triangle ABC is set in a vertical plane as shown in the figure Two beads each of mass m and carrying charges q and 42 are connected by a cord of length and kept between the arms AB and AC of the triangle in such a way that they can slide without friction along the arms When the beads are stationary determine i the angle a ii the tension in the cord and iii the normal reaction on the beads B 30 Pat a A 92 Q 60 C Fig 2 22 a If the cord is now cuts what are the values of charge for

equivalent resistance between points 4 and B in the following diagram is 20 20 20 20 202 wwwwwwwwwwwww 202 Aww Boy 20 on www w 202 20 wwwww en 40 wwwwww www 20 20 202

3 varies as where r is the distance from the 1 where r is the distance from the axis r A parallel plate capacitor is charge to certain P d A slab of thickness 3mm is inserted between the plates and it become necessary to increase the distance between plates by 2 2 4 mm to maintain the same P d The dielectric constant of slab is 1 3 2 5 4 varies as r 3 2 5 4 2 4 and 30 at some distance apart attract each came distance

Two bulbs consume same power when operated at 200V and 300V respectively When the bulbs are connected in series across a D C source of 500V then ratio of potential difference across them is 2 3 ratio of potential difference across them is 4 9 ratio of power consumed across them is 4 9 Oratio of power consumed across them is 2 3

Calculate the reading of voltmeter between X and Y then Vx Vy is equal to 1F A 1 10 V 2F HH 3F X 1F 6F 20V 2 13 33V B 16

In the circuit shown the reading of the Ammeter becomes four times of its initial value after the switch is closed Each resistor has a resistance 20 and the ideal cell has e m f 10 V Then the ammeter has a resistance in 2 equal to www switch www

57 In the circuit shown if a conducting wire connected between points A and B the current in 2006 this wire will 402 192 B c Be zero d Flow from B to A 352 a Flow from A to B b Flow in the direction which will be decided by the value of V 100

Every atom makes one face electron in copper If 1 1 ampere current is flowing in the wire of copper having 1mm diameter then the drift velocity appox will be Density of copper 9 10 kg m and atomic wt 63 1 0 3 mm sec 3 0 2 mm sec 2 0 1 mm sec 4 0 2 cm sec

Find VAR PN diode is ideal AB 1 10 V 30 V I VAB 10 Q 10 22 10 2 2 20 V

When a second resistor is added as shown the 6V battery pushes charge 1 through a total resistance of 2 52 6V 202

Two cells of unequal EMF E and E2 and internal resistances and 2 are joined as shown in figure V and V are the potential at P and Q respectively P This question has multiple correct options 0 E HH E Q The potential difference across both the cell will be qual 4 One of the cell will supply energy to the other cell Your Answer You Missed

32 A ring is made of a wire having a resistance R 1202 Find the points A and B as shown in the figure at which a current carrying conductor should be connected so that the resistance R of the sub 8 circuit between these points is equal to 3 l a C l l l 5100 3100 l 3 8 8 A l 2 b d B l l l 3 1 2 2012 Pre amb a 37 Th CO 01 re E T be a C

Four identical long solenoids A B C and D are connected to each other as shown in th figure If the magnetic field at the center of A is 3 T the field at the center of C would be Assume that the magnetic field is confined with in the volume of respective solenoid A 000000 i 9 T 12 T B oooooo 000000 000000 D C

In a portion of some large electrical network curents in certain branches are known as shown in figure 652 252 A WH 3V The value of VA Vc is O 76 V O 76 V O 58 V O 52 V 7A www 5V 40 4V F 852 9V MATE www wwwD 2A 1002 3A

Twelve wires each of resistance r ohms are connected in the form of a skeleton cube Find the equivalent resistance of the cube when the current enters at one corner and leaves at the diagonally opposite corner UTION

Example 29 a Estimate the average drift speed of conduction electrons in a copper wire of cross sectional area 1 0x107m carrying a current of 1 5 A Assume that each copper atom contributes roughly one conduction electron The density of copper is 9 0 10 kg m and its atomic mass is 63 5 u Take Avogadro s number 6 0 10 3 mol 3 b Compare the drift speed obtained above with i thermal speeds of copper atoms at ordinary temperatures ii speeds of electrons carrying the current and iii speed of propagation of electric field along the conductor which causes the drift motion NCERT

Current passing through cells is 2V W 11 0 40 4V ww 1 19 90 AW 1 0 4 A 2 0 2 A MW MW 6 Q 3 01A 4 None

In the following circuit Vsource 12 V and V V What is V3 1 1 Point 4 0 V 3 0 V 6 0 V 12 0 V V source V V

32 Which two of the four circuits given below are identical with respect to the current through resistor X 5V 7V 2 V 1 3 12 V wwww 292 www X ww 1 292 wwwww 3Q 2 4 ww www X 12 V 522 www 502 www

In a portion of some large electrical network currents in certain branches are known The values of VA VB and Vc VD are X and Y respectively where X and Y are A X 29 V Y 26 V C X 58 V Y 52 V A 7A 202 H 3V 5V 852 TOV 40 4V C B X 58 V Y 52 V D X 29 V Y 26 V wMD 6 92 2 A wwwww 10 2 13 A E

59 The equivalent points O and A is 1 3 12R 13 5R C resistance of the circuit between 5R 2R B R R 5R 2 AY A R 13 15R ON REDMI 7 AI DUAL CAMERA SHOT

9V The current through the A C 30 resistor is 0 5 A 40 resistor is 0 5 A 80 W 20 202 www 20 B D 202 80 wwww 20 40 30 resistor is 0 25 A 40 resistor is 0 25 A

done by external forces to increase their separation to 2a Two identical particles each having a charge of an electron lying 10 cm apart are released What will be their ke 2 speed when they are 20 cm apart 2x10112 i Determine the electrostatic potential energy of a system consisting of two charges 7 C and 2 C and uternal fiold placed at 9 cm 0 0 and 9 cm 0 0 respectively

of electron inside conductor between two consecutive collision when no potential difference exists between the ends of conductor 1 Stright line 2 Parabolic 3 Circular 4 Zig zag

In the following circuit diagram an infinite series of resistances is shown Equivalent resistance between points A and B is 192 B 192 292 A infinite 192 292 122 292 B zero to to