Current Electricity Questions and Answers

4 The drift speed varies randomly On increasing the temperature of a conductor its 4 resistance increase because 1 Relaxation time decreases 2 Mass of the electrons increases 3 Electron density decreases 4 None of these 4 kaf Rifer 1 fenfeased and 2 4 questione

A galvanometer of resistance 1500 shows full scale deflec tion for a current of 20 mA What is the resistance that should be connected in series with it to get a voltmeter of range 0 30 V 1350

1 35 C 2 40 C 3 45 C 4 None of these The current through a wire depends on time as 45 i i at where i 10A a 4 A S Then the charge crossed through a section of the wire in 10 sec is 1 100 C 3 300 C 2 500 C 4 None Telegram 1 35 C 3 45 C fa frufe B i i at a 1 100 C 3 300 C 2 40 C 4 i 10A a 4 A S a 10 g m m 2 500 C 4

A milliammeter with full scale deflection at 100 A has a resistance of 750 Find the resistance necessary to use the instrument as a voltmeter to read 0 50 volts a resistance of 499 25 kn is to be connected in series

The resistance of a moving coil galvanometer is 99 and the current for its full scale deflection is 100 A To con vert the galvanometer into an ammeter to read a maxi mum current of 10 mA what should be the resistance to be connected in parallel with it 10

The resistance of a galvanometer is 100 and it shows full scale deflection for 1 mA current What is the resistance of the shunt to be used to convert this instrument into an ammeter to read current up to 10 A HS 05 0 001

The resistance of a moving coil galvanometer is 5000 and the current required for its maximum deflection is 10 A To convert the galvanometer into a voltmeter to read a maximum voltage of 100 mV what should be the resistance to be connected in series with it 9 5 km

A galvanometer of resistance 2000 can withstand a maxi mum current of 1 mA What is the resistance of a shunt that should be connected in parallel to get an ammeter of range 0 1 A 0 22 approx

Find VA VB in given circuit if 15V I 5A A www1 192 0000000 5mH i Current is decreasing at the rate 10 amp sec ii Current increasing at the rate 10 amp sec iii Current is constant B

50 A circuit consists of five identical conductors as shown in figure The conductors are now connected by two wires of zero resistance as indicated by dotted lines The ratio of net resistances after and before addition will be 2 3 7 1 IS

4mm AL C G Circuit P Circuit Q For the solenoids shown in the diagram which are assumed to be close to each other the resistance of the circuit P is increased uniformly with time The current flow through galvanometer G is 1 from B to A and is constant 2 3 from A to B and is constant decreasing and from A to B increasing and from A to B B

1 V 2 2V 3 4V 4 2V 19 9 Two metallic concentric shells are shown Questi closing the switch charge on inner shell is charge on outer shell is 2Q Potential at point A is V What will be potential at same point after closing the switch 2a 1 V 3 MI4 2 2V ilm 1 V fava 1 V Ce 2 2V 16 2a 3 4V en 4 2V 20 2 2V

17 The expression for the equivalent capacitance of the system shown is A is the cross sectional area of one of the upper plates AL klo ga A O 3d 1a1 1140 a d da 3a 2 4 sofa 3A 0 d 6 A80 KAZC 4 3d 3d keq KAGO

The galvanometer shown in figure has resistance 5 0 Main current of 6 A passes in circuit as shown If current through galvanometer is lg then 6 A 10 10 17 15 5 4 Q wwww 192 5 V A when switch S is closed A when switch S is closed A when switch S is open lg 0 A when switch S is open S

28 The reading of voltmeter S in the circuit as shown in figure will be 12 V 1 4 V 3 9 V 20 2 wwww 60 2 ww 30 2 S 2 6 V 4 10 V 33 34

12 When an additional resistance of 1980 2 is connected in series with a voltmeter then the scale division reads 100 times larger value Resistance of the voltmeter is a 102 b 20 2 30 d 40 Q potentiometer circuit has been set w ance of a given cell The ometer wire he esistan b 7 9 Q d 6 9 Q the potentiome V cm is

Two identical cells connected in series send 10 A current through a 50 resistor When they are connected in parallel they send 8 A current through same resistance What is internal resistance of each cell 2 5Q 10 O 1 50

Find the capacitance of a multiple plate capacitor made from 30 pairs of 10x15mm rectangular plates separated by 50nm of polystyrene k 2 6 If a 4uF capacitor is connected to a constant current source therefore its current is given in the equation ic t 10mA Determine the voltage power and energy at 2ms

4 a A few identical cells are first joined in series and then in parallel Under what condition will both the combination send the same current though the external resistance R b In a closed coil there are n number of cells connected in series E M F of each cell is e internal resistance r and the connecting wires are resistanceless What reading will the voltmeter give when connected across any one of the cells Assume that the voltmeter has infinite resistance

20 resistance is connected in series of a cell of emf 2 2 volt The voltmeter across the resistance reads 2 V thus internal resistance of the cell is A B 0 2 0 0 10 10 40

29 resistance is connected in series of a cell of emf 2 2 volt The voltmeter across the resistance reads 2 V thus internal r the cell is A B D 0 292 0 192 192 Mark 452

34 35 36 37 38 39 40 41 42 43 A zener diode having breakdown voltage equal to 10V is used in a voltage regulator circuit shown in figure The current flowing through the diode is 1 10 mA 2 5 mA 3 Question Type Single Correct Type 15 mA 20002 ww 20 mA ISV OV English Review www 1612

Digital Classroom NEETUO Physics 17 18 19 20 21 22 23 24 25 26 10 20 0401 20 resistance is connected in series of a cell of emf 2 2 volt The voltmeter across the resistance reads 2 V thus internal resistance of the cell is Question Type Single Correct Type 20 10 101 13 3 10 02 56 47 40

5 A point charge Q is moved along a circular path around another fixed point charge The work done is zero only if Q returns to its starting point only if the two charges have the same magnitude only if the two charges have the same magnitude and opposite signs in all cases

7 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 both A and V will increase both A and V will decrease A will decrease V will increase A will increase V will decrease

1 Capacitance of a parallel plate capacitor can be increased by a increasing the distance between the plates b decreasing the distance between the plates c decreasing the area of plates d increasing the thickness of the plates

rcuit shown is 6V 400 www 1 2 25 V 2 3 25 V Hint Equivalent resistance of voltmeter is resistors ie 40 Q and 24 2 600 ww V 400 3 4 25 V 60 x 40 60 40 4 6 25 V 24 2 Now PD is in the ratio of series

When an incandescent electric bulb glows A the electric energy is completely converted into light energy B the electric energy is partly converted into light energy and partly into heat energy C the light energy is converted into electric energy D the electric energy is converted into magnetic energy

35 A R 1502 www R 1002 www R 300 wwwww Find the resistance across AB R 2002 www B

The current in the given ciruit is 4 8 VT R 302 ww R 60 1 1 6 A 2 2 A 3 0 32 A 4 3 2 A Hint R R are in series and then R in parallel I VIR eq not be considered R 6n

44 Potential difference across AB in the network shown in figure is 1 2 V 2 3 V 3 1 V 4 1 5 V ww 30 92 www 30 92 B 1592 www 3 V 50 Tower 8 Pusa Road New Delhi 110005 Ph 011 47

10 Find the effective resistance between points A and B BREDBE www 19 10 192 wwww 192 1 3 1 C L wwww 192 192 www www 192 192 wwww 1 2 A www www 12 122 LM www B 192 wwww www 192 19 www 12 2 3 1 1 3 3 1 www 19 aas

In the circuit in figure we have 2 100V R 200 R 10 Q R3 400 and R2 R4 30 Q Find the reading of the ammeter in A Disregard the resistance of the battery and the ammeter 182 A 1 04 R R R Question Type Numerical Type R

Mass of Calculate the dc collector voltage V with respect to ground in the amplifier circuit shown in the figure The current gain B for the transistor is 200 6k HH 3kn 1 9V 0 7V 4kQ 2 3ks Vc

10V 43 Calculate the Norton resistance for the following circuit if 5 ohm is the load resistance 3 ohm O 10 ohm O 11 ohm 6 ohm 10 ohm www B ENGINEERING REMAINING TIME HOURS MINUTES SECONDS 1 56 ohm O 12 ohm O13 ohm

Three monochromatic 12 42nm 6 21nm each other in front of a converging lens such that equal powers from the three equal to 1mW each fall on a converging lens and then on a small spherical conductor of radius r 1mm and work function 62 1eV Assume 50 efficiency of emission and no change in effective value of work function due to photoelectric emission and potential rise Use hc 1242eV nm All electrons emitted by the sphere are immediately removed by some non electrical mechanism At t 8 sec switch S is closed so that the sphere gets connected to the earth via a resistor of value 6 750 Find the current flowing just after the switch is closed S S S3 sources having wavelengths and 24 84nm are placed close to Your Answer 2 5 R R Ground

Q3 The effective resistance for the below circuit is UT O 252 1 6 Q 2 422 2 802 5 6 Q 152 252 152 U

R www V If switch is closed 1 v increases 2 Both V and R www minimum R www V 2 suonon and v decreases V increases S 3 Both v and v decreases

The equivalent resistance between A and B as shown in the given circuit is 692 wwwww 402 www 692 30 50 40 60 B

In a series LCR circuit the frequencies f and 1 f at which the current falls to 1 current amplitude at resonance are separated by frequency interval R 2 2 21 VLC of the 3 VLC 4 RC 29

Two identical bulbs are connected as shown in figure across a cell of emf E and internal resistance r The brightness of B when bulb B gets fused will T B 8 a Increases b Decreases c Remains constant d Becomes zero

2 A current is flowing through a conductor which is in the shape of truncated cone If V and V be the drift speed at section 1 and section b then a V V c V V b V V d Any of these

The series combination of two batteries both of the same emf 10 V but different internal resistance of 20 2 and 5 2 is connected to the parallel combination of two resistors 30 22 and R 22 The voltage difference across the battery of internal resistance 20 2 is zero the value of R in 2 is Main 8 Jan 2020 II

For a cell a graph is plotted between the potential difference V across the terminals of the cell and the current drawn from the cell The emf and internal resistance of the cell are V volt 4 3 2 1 of 0 1 2 V and 22 3 2 V and 42 I A 2 4 V and 22 4 4 V and 49 N

e elapsed in the process is S 23 A battery of EMF 10V sets up a current of 1A when connected across a resistor of 89 If the resistor is shunted by another 89 resistor what would be the current in the circuit in A

In the diagram AB is a uniform resistance wire J is a sliding contact which starts sliding at time t 0 from end A towards end B with constant velocity Vo Length of AB is l as shown Power loss in AB at time t will be wwwwwww B A J 0

Is Eg 1 Y bisons 6 50 ww 7 602 Internal resistances are 0 5 ohm 0 4 ohm respectively and E1 15 V and E2 12 V If switch S is 1 open 2 closed By applying Kirchoff s law calculate the value of 11 12 and 13 and the current in each of the remaining branches of the network shown in figure

3 Zero 4 4E 25 The emf and internal resistance of single batter which is the equivalent to the combination of thre batteries as shown in figure are 6V 1 2V 30 3 20V 202 www 192 10V 202 www www 4V 202 2 3V 202 4 2V 2002

Consider a conductor of resistance 50 through which 31 25 x 1010 electrons a re flowing for 5 minutes Calcul ate the amount of current flowing throu gh it Also find potential difference acro ss it

In the given AC circuit current and potential difference across the resistance inductor and capacitor are shown in figure Then which of the following options is are correct 1A R 50 V 20 Volt V 30 Volt www HH current leads the voltage in phase B Voltage leads the current in phase RI Power factor of the circuit is Applied voltage is 15 V 1