Current Electricity Questions and Answers

SS KOTA 48 30 19 10 202 wwww 212 A fr www 202 2X Find the value of I 1 1 4 A 65 2 2 1 A 4 4 2 A 2 TSV SA

3 1 25 V cm What is the emf of the second cell 2 1 5 Voley 4 2 25 V PO 14 A wire carries a current of 2 0A What is the charge that has flowed through its cross section in 1 0 sec 14 How many electrons does this corresponds to pg 9 1 0 2 C 1 25 10 9 3 2C 1 25 x 10 19 2 2C 1 25 x 10 9 4 0 2C 1 5 x 101 C 15 The temperature coefficient of a wire is 0 00125 C At 300K its resistance is one ohm The resistance of the wire will be 2ohm at 1 1154 K 2 1100 K 3 1400 K 4 1127 K 16 Two wires A and B of the same material having radii in the ratio 1 2 and carry currents in the ratio 4 1 0 The ratio of drift speed of electrons in A and B is pg 1 1 16 1 pg 9 confusing 2 1 16 3 1 4 24 4 4 1 7 When a current I is set up in a wire of radius r the drift velocity is Vd If the same current is set up through a wire of radius 2r the drift velocity will be 1 4 Vd 2 2Vd 3 Vd 2 2 OS 4 Vd 4 8 Five equal resistances each of resistance R are connected as shown in the figure A battery of V volt is The current flowing in AFCEB will be

A circular loop has a resistance of 40 2 Two points P and Q of the loop which are one quarter of the circumference apart are connected to a 24 V battery having an internal resistance of 0 5 Q2 What is the current flowing through the battery A 0 5 A C 2A B 1A D 3A

Kirchhoff s first law i e EI 0 at junction deals with the conservation of A charge B energy C momentum D mass

Four resistances 10 10 10 22 and 15 Q2 form a Wheatstone s network What shunt is required across 15 2 resistor to balance the bridge A 10 Q2 C 20 S B 15 Q2 D 30 2

1 In the following diagram through 252 resistor is 202 a 92227 A 302 6V 452 b 7229 A A the current AIIMS 2018 3V

70 The current in the given circuit is 10 Q 5 V a 03 AO t 2 V 0 002 b 04 A ww 20 Q 0 0 A OB d 0 3

The charge flowing through a resistance R varies with time t as Q at bt where a and b are positive constants The total heat produced in R is NEET I 2016 XR 1 3 a R 6b a R ub 2 4 a R 3b a R

1 A resistor of resistance R is connected to an ideal battery If the value of R is decreased then the power dissipated in the resistor will a increase c remain unchanged b decrease d None of these

hollow cylinder has length radius r and thickness d where r d and is made of a material with resistivity p A time varying current I flows through the cylinder in the tangential direction Assume the current is always uniformly distributed along the length of the cylinder The cylinder is fixed so that it cannot move assume that there are no externally generated magnetic fields during the time considered for the problems below Assume current at t 0 to be I What is current I t for t 0 P t 1 I Ie 2Hord 2 I Ine 3 I Le 2p t Hord 2 ord Hordt 4 I Ine 2p PU

A galvanometer of resistance 95 2 shunted by a resistance of 5 2 gives deflection of 50 divisions when joined in series with resistance of 20 k2 and 2 0 V accumulator The current sensitivity of the galvanometer in division per HA is

A body has a negative charge of 2 C If body has 2 25 x 10 2 protons then number of electrons present in the body will be a 1 25 x 1012 c 1 x 1012 12 b 2 25 x 1012 d 3 50 x 10 2

certain circuit current changes with time according to i 2 t r m s value of current between t 3 s ec will be TITO spirmsst 4s

A negligibly small current is passed through a wire of length 15 m and uniform cross section 6 0 x 107 m and its resistance is measured to be 5 0 22 What is the resistivity of the material at the temperature of the experiment

A resistor resistance A 400 Q B 940 is labelled 400 2 5 the true is lies between 380 2 and 420 S D 416 7 S

between A and B in the situation shown is 2 R 2 R 8R 3 www wwwww A R R 6R 3 R 5 he situation shown the potential difference across the cell of smaller e m f is B 4 2R

8 A step down transformer reduces the 53 6 supply voltage from 220 V to 11 V and increase the current from 6 A to 100 A 3 52 Then its efficiency is a 1 2 c 0 12 2 for 0 d 0 9 0 83

OTEN It is observed in a potentiometer experiment tha no current passes through the galvanomete when the terminals of a cell are connected acro a certain length of the potentiometer wire shunting the cell by a 2 2 resistance the balanc length is reduced to half The internal resista of the cell is 1 4 2 2 20 4 18 Q

For the following circuit R R 60 02 R3 250 02 R4 325 02 R5 260 0 2 and V source 35 V What is 14 R 65 mA 37 mA 82 mA R R R R3

Two batteries with emf 12 V and 13 V are connected in parallel across a load resistor of 100 The internal resistances of the two batteries are 19 and 202 respectively The voltage across the load lies between 11 6 V and 11 7 V 11 5 V and 11 6 V 11 4 V and 11 5 V 11 7 V and 11 8 V A C B D 2018

9 In the circuit shown in the figure the voltmeter reading is 6 V a 2 4 V c 4 0 V V 60 Q 40 2 b 3 4 V d 6 0 V coil

9 For the resistance network shown in figure choose the correct option s 292 wwwww S 10 292 492 1 1 A Current through PQ is zero C Potential at S is less than that at Q www 2 192 193 www 4 92 12 V T www 292 492 wwwww B 1 3A D 2A

22 The resistors are connected as shown in the Fig 18 MT 8 Find the equivalent resistance be tween the points A and B FIGURE 18 MT 8 302 D A 7Q www 1022 www 1092 C B 59

the on off switch when it is on as shown 1 Point 0 32 A 0 38 A 0 23 A 11 ohm CIFT WID 5 ohm 12 ohm II I WID 20 V ON 24 ohm 8 ohm C 20 ohm 5

What is the total equivalent resistance of this circuit 1 Point 2 6V 60 Q 48 Q2 15 Q 4 2V W 3 20052 M 1 0 25A Vp 120 8 0 5 A ww M 7 7V W 5 3 V W 6 203

efine electric current Is it a scalar or a vector Mention its S I unit

For the following circuit the resistances are R 220 R 360 N and the total resistance for the circuit is 436 Calculate the resistance of R 1 Point R H 440 Q 540 Q 520 Q 390 Q R R

In the circuit R R R 250 and R 300 2 12 0 V and V 3 0 V find R1 If Vsource 1 Point V source 20 Q 232 Q 91 Q R M R R3 R

7 A square aluminium rod is Im long and 5mm on edge What must be the radius of another aluminium ro length is I m and which has the same resistance as the previous rod 1 5 mm V sonensfil 2 4 2 mm T ni nwor3 2 8 mm olavas 4 1 4 mm 13 An electric current of 5A is passing through a circuit containing three wires arranged in parallel If the leng radius of the wires are in the ratio 2 3 4 and 3 4 5 then the ratio of current passing through wires w 4 54 64 75 1 3 6 8 2 4 9 16 3 9 16 25 14 A current of 6A enters one corner P of an equilateral triangle PQR having 3 wires of resistances 20 ead leaves by the corner R Then the current I and I are 8 ww 6A AP DOBRETO

For the following circuit R 75 2 R 125 2 R3 1052 R4 150 and V 15 V What is V source R V R H I H 55 V 45 V 35 V 40 V ama R R

55 Find the potent 16 3Q www 2 A 1 48 volts ms 05 3 4 volts 48 Q www 48 Q www 24 22 wwww 62 www 40 www 222 50 www 2 2 volts 4 1 volts

24 Each of the resistances shown in figure 45 E2 has a value of 20 2 Find the equivalent resistance between A and B Does it depend on whether the point A or B is at higher potential A Figure 45 E2 B A 30

www 12 V 1 IV 2 2 V 3 3 V 4 4 V In the circuit given below the ammeter reading is zero What is the value of resistance R 50002 1 50 2 www B 2 V 5V 2 502 2 100 2 A 3 200 S2 4 400 2

51 Eight resistances each of 4 ohm are connected in the circuit as shown in figure The equivalent resistance between A and B is C a c 13 a b d 8 SE SE a Q Q 492 4Q D MM www www 492 A wwwww 4 49 49 ww 452 49 B 422 www

58 Which of the following graph represents the variation of resistivity p with temperature T for copper T 1 2 3 4 P P P P T T T

A and B are two conductors carrying a current i in the same direction x and y are two electron beams moving in the same direction A B X y 1 There will be repulsion between A and B attraction between x and y 2 There will be attraction between A and B repulsion between x and y 3 There will be repulsion between A and B and also x and y 4 There will be attraction between A and B and also x and y

3 16 Two wires A and B of the same material having radii in the ratio 1 2 and carry currents in the ratio 4 1 0 The ratio of drift speed of electrons in A and B is pg 9 Confiring 4 1127 K 1 16 1 2 1 16 3 1 4 4 4 1 17 When a current I is set up in a wire of radius r the drift velocity is Vd If the same current is set up through a wire of radius 2r the drift velocity will be 1 4 Vd 2 2Vd 3 Vd 2 4 Vd 4 18 Five equal resistances each of resistance R are connected as shown in the figure A battery of V volt is connected between A and B The current flowing in AFCEB will be C www R C R F R R B E ns 2

4 D 25 In the given circuit two cells of different internal resistance 6 2 and 22 but same emf are connected in series with external resistance R If potential difference across cell of internal resistance 62 is zero then R is E 1 20 Q E 69 WW R ww 22 HHWW 2 89

16 The measurement of voltmeter in the following circuit is 6 V 40 Q 60 40 Q

30 Two resistors of resistances R and R R R are connected in parallel For equivalent resistance R the correct statement is b R R R a R R R c R R R R d R R

2006 After the capacitor gets fully charged S is opened and S is closed so that the inductor is connected in series with the capacitor Then A at t 0 energy stored in the circuit is purely in the form of magnetic energy B at any time t 0 current in the circuit is in the same direction C att 0 there is no exchange of energy between the inductor and capacitor fully D after time interval 2t charge on the VERE D at any time t 0 instantaneous current in the circuit may V

4 1980 The temperature coefficient of resistance of a wire is 0 00125 per C At 300 K its resistance is 192 This resistance of the wire will be 20 at A 1154 K C 1400 K tion Ru B 1100 K D 1127 K COGNATIONES PRIVATE JE

The resistance of a wire is 5 ohm at 50 C and 6 ohm at 100 C The resistance of the wire at 0 C will be 2007 1 2 ohm 3 4 ohm 2 1 ohm 4 3 ohm

For current entering at A the electric field at a distance r from A is 1 pl 8 2 3 pl 2 r 4 pl 4 r

9 In the circuit shown in the figure no current flows through the 802 resistor then the potential difference between points A and B VA VB is 94 20 A 1 14V 2 12V 3 26V 4 12V 4mm 8V 180 20V HH 892 X 6V 8V B HTC 18

6 What will be the potential gradient umbet specific resistance of a potentiometer wire is 107 ohm meter and current in the primary circuit of a potentiometer wire is 0 1A cross section area of the potentiometer wire is 10 m A 10 V M B 10 V M C 102 V M D 10 V M

and equal internal resistance rare given A resistor of resistance R is connected in all four situations a capacitor of capacitance C is connected in last two situations as shown Four statements are give column II Match the situation of column I with statements in column II Column I A B C D E r E r R www R The capacitor is initially uncharged After the key closed K is Er P 5 E2 r E r R www LK C TE 1 P 9 R The capacitor is initially uncharged After S the key K is closed R C 666666 Column II Magnitude of potential difference across both cells can never be same Cell of lower emf absorbs energy that is it gets charged up as long as current flows in circuit Potential difference across cell of lower emf may be zero Current in the circuit can never be zero even after steady state is reached

A wire of uniform cross section A length and resistance R is bent into a complete circle the resistance between any two of diametrically opposite points will be R R 2 4 1 2 3 R 8 4 4R

3 When negative charge given to soap bubble it a expands b contracts c may expand or contract di remains same

4 A Bis 2r 3 www 1 r 3 4r 3 www www r www www 2 2r 4 7r wwww wwww B