Current Electricity Questions and Answers

If a voltage of 2 5j and another voltage of 3 6j flows through two different resistors connected in series in a circuit find the total voltage in the circuit Answer A B C D 2 5j V 3 6j V 5 11j V 5 10j V

hick 81 In the circuit shown from A to B then A A www 20 9 ww 5Q W w 59 D 209 B is passing 1 No heating and no current between C and D 2 C and D are at the same potential 3 Current of 3 A flows from D to C

The part of an electrical circuit that converts electrical energy into other forms of usable energy The unit used to measure energy usage The reason incandescent bulbs have been banned in Canada is because they produce so much 726kWh 600 kWh m 43cm per year par ann e 937 K A circuit in which the loads are connected by branches so that there are two or more paths for electrons to follow A device used to measure electric current A device used to measure potential difference in a circuit A EnerGuide label B voltmeter C parallel D ammeter E load F resistor G heat

b A 10m long potentiometer wire carries a steady current A 1 018 V standard cell is balanced at a length of 850cm Find i the potential gradient along the wire ii the maximum emf that can be measured 5

11 A house has a lamp in every room The circuit for the lamps is shown The voltage drop across the energy source is 120 V The total resistance is 10 Q TA a Calculate the current through each lamp 6 Given 1 Statement 1 Formula s Equation s and Answer 4 b Calculate the voltage drop across each lamp 4 Given 1 Formula s Equation s and Answer 2

The equation for an alternating current is given by i 77 sin 314t Find the peak value frequency time period and instantaneous value at t 2 ms Answer A B A C A D Im 77 A T 0 02 s i 45 24 A Im 15 A T 0 14s i 25 24 Im 100A T 0 25 s i 10 24 Im 12 A T 0 65 s i 11 24 A

10 The total resistance of this circuit is 25 2 The voltage drop across the battery is 6 0V T I XXX a Calculate the current in the circuit 4 Given 1 Statement 1 Formula s Equation s and Answer 2 b Calculate the voltage drop across each lamp 3 Formula s Equation s and Answer 2 Statement 1

S 5 A galvanometer having internal resistance 10 requires 0 01 A for a full scale deflection To convert this galvanometer to a voltmeter of full scale deflection at 120 V we need to connect a resistance UK PMT 2014 of a 11902 in series c 1201092 in series b 11990 2 in parallel d 120102 in parallel nt a cell of emf 1 25 V

2 19 Choose the correct waveform that can represent the voltage across R of the following circuit assuming the diode is ideal one V 10 sinot tions 3 1 N N 2 3 4 3 3 3 3 3 V R 3 3 3 V t f t

In the situation shown in each cell has e m f 4 V and int al resistance 10 The maximum power that can be delive ed to the variable load resistance R is Board Competitive Exams Level 1 22 In the situation shown each cell has e m f 4 V and internal resistance 1 92 The maximum power that can be delivered to the variable load resistance Ris 1 64 W 2 32 W 27

A 6 A voltmeter has a least count of 0 1 V and an ammeter has a least count of 0 1 A The potential drop V across a resistor is measured as 10 0 V and current through it is measured as 1 0 A The value of resistance with error is 1 10 1 1 S 3 10 0 5 9 2 10 1 Q 4 10 0 2 S

where all resistor are of 1k If a current of magnitude 1mA flows through the resistor marked X What is the potential difference measured between points P and Q P 1 21V 2 68V 3 55V ww ww X

The current in a conductor and the potential difference across its ends are measured by an ammeter and a voltmeter The meters draw negligible currents The ammeter is accurate but the voltmeter has a zero error that is it does not read zero when no potential difference is applied Calculate the zero error if the readings for two different conditions are 1 75 A 14 4 V and 2 75 A 22 4 V

In the circuit shown in figure find the value of r internal resistance of the cell for which power transferred by the cell is maximum 50V 1 40 2 12 3 160 4 80 1292 4592 V www 452 www 1292

24 Two bulbs A and B are connected as shown When switch S is closed then which of them wi fuse 100 V 50 W 100 V 40 W A B 200 V 1 Bulb A 2 Bulb B 3 Both A and B will fuse S

Q 16 In the circuit shown switch is connected to 1 for a very long time At a particular instant t 0 switch is shifted to 2 the current in the circuit after a time gap of is ereivel 1 2L 0000000

What is the equivalent resistance between the points A and B of the network 392 202 A 1 2 3 57 80 292 www 60 403 1022 wwww 1 892 wwwww Question Type Single Correct Type wwww 2 252 122 1Q2 www 592 B

A flows in a system of conductors as shown potential difference VA VB will be Odisha JEE 2011 12 ev V 2A D 292 30 www 302 20

A spherical shell of radius R is given charge 3q on its surface and a point charge q is placed at distance R 2 from its centre C Also there is a charge 2q placed outside the shell at a distance of shown Then 1 2 3 4 root Answer 134 R 2 C Ka The electric potential at the centre C due to charges on the outer surface f shell is R 2R The magnitude of electric field at the centre C due to charges on the outer surface of shell is Kq 2R2 before closing the switch S Kq The electric potential at the centre C due to charges on the outer surface of shell is R Charge flown through the switch into earth after closing the switch S is 5q 2q before closing the switch S after closing the switch S

2 An ac voltmeter connected between points A and B in the circuit below reads 36 V If it is connected between A and C the reading is 39 V The reading when it is connected between B and D is 25 V What will the voltmeter read when it is connected between A and D Assume that the voltmeter reads true rms voltage values and that the source generates a pure ac a 481 V A mm B O b 31V

There is a system of four large parallel plates A B C and D Plates A and C are connected to each other with the help of metallic wire and plates B and D are connected to the ground with the help of open switches S and S Distance between consecutive plates is d Initially plates A and B are having a charge of Q each and plate D is having charge 2Q See figure At t 0 switches S and S are closed simultaneously Then the magnitude of charge flown through switch A S is 5Q 3 B S is Qo C S is 7Q 3 D S is 2Q Q d d Q B d 20 D

An ammeter and a voltmeter are joined in series to a cell Their readings are A and V respectively If a resistance is now joined in parallel with the voltmeter 1 both A and V will decrease 2 both A and V will increase 3 A will increase V will decrease 4 A will decrease V will increase

In the circuit shown in the figure 3 volts E2 2 volts E3 1 volt and R r r r3 1 Find the potential difference between the points A B and the currents through each branch A R 11 12 1 3 ww E2 E1 E3 B

Resistance in the two gaps of a meter bridge are 10 ohms and 30 ohms respectively If the resistances are interchanged the balance point shifts by 1 33 3 cm 3 25 cm 2 66 67 cm 4 50 cm

QIn the circuit shown in figure E 3V E2 2V E3 1V and 1ohm r1 r2 73 a Find the potential difference between the points A and B and the currents through each branch b If r2 is short circuited and the point A is connected to point B through a resistance R find the currents through E1 E2 E3 and the resistor R l 1 E1 A 1 2 I 3 E E3 B VIEW ANSWER

The circuit diagram shows that resistors 20 40 and RN connected to a battery of e m f 2 V and internal resistance 3 A main current of 0 25 A flows through the circuit What is the p d across the R and 2 resistor 0 25 A 2V 292 wwww wwwww RQ 492

In the circuit shown in figure belwo E 17V E2 21 V R 2N R 3N 50 Using Kirchhoff s laws and R3 find the currents flowing through the resistors R R2 and R3 Internal resistance of each of the batteries is negligible A R 11 F R1 BR R3 I E R C D 12

In Figure 1 6 00V 2 12 0V R 100N R 2009 and R3 300 One point of the circuit is grounded V 0 What are the a size and b direction up or down of the current through resistance 1 the c size and d direction left or right of the current through resistance 2 and the e size and f direction of the current through resistance 3 g What is the electric potential at point A A www R www 8 R www R E28

Q45 A battery of e m f 10 V and internal resistance 3 2 is connected to a resistor and the current in the circuit is 0 5 A The resistance of the resistor and the terminal voltage of the battery when the circuit is closed are O A 17 Q and 8 5 V respectively O B 8 5 Q and 17 V respectively c 30 Q and 10 V respectively O D 30 and 10 V respectively

In the circuit shown in figure 32 E13 3 V 2 2 V 3 1 V and 1 Find the potential difference between the points A and B and the the current through each branch r1 7 3 10 r2 l 1 12 2 3 B

V230 V 0 192 1 22 0 06 2 Fig 2 80 determine the branch currents using Kirchhoff s laws 0 05 1 192 1151 35A 224 55A 27 7A 179 05 A 196 84 A

resistance R of the circuit shown in Fig if the resistances are equal to R 10N R 20 and R3 30 and the potentials of points 1 2 and 3 are equal to 1 10 V 42 6 V 43 5 V and R R R3 3

internal resistance r is connected across an external resistance R The maximum power is external circuit is 9 W The current flowing through the circuit in these conditions is 3 A Then which of the following is are correct

28 29 1 3Q 2 22 3 692 4 36 2 Reading of Ammeter A and respectively 30V 3092 30V 3002 A and A will be 28 A 10V 1092 20V ouree 1092 30V A 1 4A 9A 2 2A 7A 3 4A 7A 4 2A 9A Three 60 W 120V light bulbs are connected 29 If resistance of 87 1 392 3 652 327 at I 30V 3052 A a 30V 3002 1 4A 9A 3 4A 7A 60 W 120V a af

Full scale deflection current for galvanometer is 1 Amp What should be the value of shunt resistance so that galvanometer shows half scale deflection A B C 10 Q 10 12 Q A 10A G 2092 S www R 1892 B My Answer

A cylindrical copper wire is stretched such that its diameter decreases by 0 01 The approximate percentage increase in its resistance is A B C 0 02 0 04 0 08 0 16 My Answer Correct Answer

Difference in balance length for two cells in potentiometre wire is 20 cm and difference in their emf s is 0 6 volt If length of wire is 5 m then potential gradient and strength of P M will be A B 2 V m 20V 3 V m 15V 2 V m 15V 30 V m 15V Correct Answer

A solid metallic cupold oi nomogeneous material having geometrical dimension as shown in the figure will have a ratio of resistances for the sense of current along x y and z directions respectively equal to Z A B C I a b c a a c b a 6 c S 2 12 b C X

Choose the INCORRECT statement s A B C D Kirchoff s voltage law is based on conservative nature electrostatic field Kirchoff s current law is based on charge conservation Battery can act as load and source both Ohm s law is applicable to semico range of voltage My Answer

Problem 3 23 How many number of turns of nichrome wire of specific resistance 10 Qm and diameter 2mm that should be wound on a cylinder of diameter 5cm to obtain a resistance of Solution If R is the radius of the cylinder r is the radius of the wire and

vibrational degree of freedom In the figure ammeters read a current of 1A each as shown while the voltmeter reads a potential difference of 3V The ammeters are identical the internal resistance of the battery is negligible Consider all ammeters as non ideal The value of resistance R shown in figure in 2 is 4V www R 12 A

A voltmeter having a resistance of 1800 is employed to measure the potential difference across 2000 resistance which is connected to dc power supply of 50 V and internal resistance 2002 What is the approximate percentage change in the potential difference across 2000 resistance as a result of connecting the voltmeter across it

connected across a resistor R A voltmeter having variable resistance is used to measure the potential difference across the resistor The plot of voltmeter reading V against G is shown What is value of external resistor R G Resistance of galvanometer 20V 10V 5V th R www

38 Five resistors each of value m are connected between points A and F as shown in figure If two similar wire resistor are connected one between points B and D and another between points C and E The effective resistance between points A and F will be 1 7 m 3 3 m A A B C 2 5 m 4 6 m LU E www G

Figure shows a potentiometer circuit The length of potentiometer wire is L and its resistance is 2R Neglect the internal resistance of the cells Select the correct alternative A B C D www R Hilt 1V 3 V R S www 2R No duflection When only S is closed When only S is closed 1 L 6 When S and So are closed 1 1 L When both S and S are closed 1 L 6 1

QAn ideal p n junction diode can withstand currents up to 10mA under forward bias The diode has a potential difference of 0 5V across it which is assumed to be independent of current What is the maximum voltage of the battery used to forward bias the diode when resistance of 2000 is connected in series with it

A conducting rod pq is sliding on two parallel conducting rods with constant velocity in a uniform magnetic field of induction B 2 Wb m2 as shown in the figure The rods are connected with a circuit What should be velocity of rod Pq if current in 20 resistor is 0 1 A 3 02 x X X 3 52 CH 65 wwwwwww i 0 1 292 A Bo x v X 122 DX X X

If the capacitance of a Van de Graaff accelerator terminal is 250 F pF and if it operates at a voltage of 4 MV what is the total charge on the terminal If the charging belt can carry a current of 0 2 mA how long does it take to charge up the accelerator to 4 MV

A heater coil is cut into two parts of equal length and one of them is used in the heater The ratio of the heat produced by this half coil to that by the original coil is 1 2 1 3 1 4 2 1 2 4 4 1

38 A carbon resistor of 56 5 6 k2 is to be marked with rings of different colours for its identification The colour code sequence will be a green blue orange silver b blue yellow orange silver c green red orange silver d red green blue gold