Current Electricity Questions and Answers

a 100 30 The resistance of wire in a heater at room temperature is 65 2 When the heater is connected to a 220 V supply the current settles after a few seconds to 2 8 A What is the steady temperature of the wire Temperature coefficient of resistance a 1 70 x 10 C a 955 C b 1055 C c 1155 C d 1258 C mire has a resistance of 2 5 2 at 28 C and a 6

1 Two 2 2 resistances are connected in parallel in circuit X and in series in circuit Y The batteries in the two circuits are identical and have zero internal resistance Assume that the energy transferred to resistor A in circuit X within a certain time is W The energy transferred to resistor B in circuit Y in the same time will be Circuit X a w b 292 202 www b W c 2 W Circuit Y 20 292 www www B d 4 W

ELECTRICAL ENERGY POWER 35 A boy has two spare light bulbs in his drawer One is marked 240 Vand 100 W and the other is marked 240 V and 60 W He tries to decide which of the following assertions are correct a The 60 W light bulb has more resistance and therefore burns less brightly b The 60 W light bulb has less resistance and therefore burns less brightly c The 100 W bulb has more resistance and therefore burns more brightly d The 100 W bulb has less resistance and therefore burns less brightly voltanerupply

a c 1020 2 C The resistance of the wire in the platinum resistance thermometer at ice point is 5 2 and at steam point is 5 25 2 When the thermometer is inserted in an unknown hot bath its resistance is found to be 5 5 2 The temperature of the hot bath is a 100 C b 200 C c 300 C d 350 C of wire in a heater at room

View In English A potential difference of 220 V is maintained across a 12000 02 rheostat as shown in the figure The voltmoter V has resistance of 8000 0 and the point c is at one fourth distance from a to b The reading of voltmotor is 1 4 55 V 50 V 45 V 6010 220V b wwwwwwwww

If voltage across a bulb rated 220 V 100 W drops by 2 5 of its rated value the percentage of the rated value by which the power would decrease is a 20 b 2 5 c 5 d 10

1 In the circuits shown below the readings of the voltmeters and the ammeters will be 1092 wwww V 10 V Circuit 1 A 1 V V and i 12 2 V V and i 12 3 V V and i 12 1092 wwww 1022 www V 2 10 V Circuit 2 A

4 Four conductors of resistance 162 each are connected to form a square The equivalent resistance across two adjacent corners is in ohm 1 6 2 18 3 12 4 16

the time a 40 C b 48 C c 38 C d 43 C 5 In an atom electrons revolves around the nucleus along a path of radius 0 72 A making 9 4 x 10 8 revolution per second The equivalent current is e 1 6 x 10 19 C a 1 2 A b 1 5 A c 1 4 A d 1 8 A ITS IN CONDUCTORS

B TH AL 4xsord KET 13 A series combination of an incandescent lamp an inductor and a capacitor is connected across an alternating voltage source Two switches A and B are provided to short circuit the inductor or the capacitor or both Initially both the switches are open and the lamp glows with a certain brightness If the switch A is closed keeping B open brightness of the lamp remains unchanged How does the brightness of the lamp change if the switch B were closed keeping A open Decreases c Remain unchanged b Increases d Insufficient information to decide

dry a 10 2 26 Two copper wires of length 1 and 2 have radii rand 2r respectively What is the ratio of their specific c 1 1 d 1 3 marked with the rings coloured brown resistances 2 1 2 b 2 1 SE E c d

c T T d I 1 2 A wire of resistance 42 is used to wind a coil of radius 7 cm The wire has a diameter of 1 4 mm and the specific resistance of its material is 2 x 107 22 m The number of turns in the coil is a 50 b 40 c 60 d 70

c 45 5 C The current in a wire varies with time according to the equation I 4 2 t where I is in ampere and t is in second The quantity of charge which has to be passed through a cross section of the wire during the time t 2s to t 6s is a 40 C b 48 C c 38 C d 43 C ans revolves around the nucleus IC

26 Thousand cells of same emf E and same internal resistance r are connected in series in same order without an external resistance The potential drop across 399 cells is found to be 1 Zero 2 399 E 3 601 E 4 1000 E

Consider the infinitely long chain of resistors shown below a R R R www R www R R w R R R R b How much electrical power is dissipated in the very last resistor at the very end of the chain It approaches W It approaches O W It is equal to the power dissipated in the very first resistor at the start of the chain closest to the terminals a and b O It is equal to about half the power dissipated in the very first resistor at the start of the chain closest to the terminals a and b

Two electric bulbs rated P watt V volts and P2 watt V volts are connected in parallel and V volts are applied to it The total power will be Question Type Single Correct Type 1 P P watt 2 P P watt 3 4 P P P P2 watt P P

1 Using the principle of superposition find the current flowing through the 12 ko resistor connected between the terminals a and b of the below given circuit 5 A a www 10 A 12 kQ2 ww 6 km2 b 6 kQ 12 kQ2 18 V

In the given branch PQ of a circuit a current 2t 3 A is flowing where t is time in second Then the value of potential difference Vp Vo at t 2 s will be port 10 V 24 V 42 V 34 V Zero www 422 ma Q 2 H

a 1 A particle of charge 3 x 10 19 C is situated in uniform electric field directed to the left In moving to the right a distance of 0 05 m the work of an applied force is 6 x 10 5 J and the change in kinetic energy is 4 5 x 10 5 J Find the magnitude of electric intensity

n the given circuit capacitor is initially uncharged and stwitch S is closed at time 0 Ratio of current passing through battery just after closing switch S and after a long time after closing the switch is C www R www R S 513 Find m

12 A point source ca metal plate Which of the following curves may represent the saturation photocurrent as a function of the distance between the source and the metal current d a C b distance Figure 42 Q1 Explain the solution please If saturation current depends on the distance b w the source and the metal the stopping potential should also depends on the distance b w COL and metal Right

A M Puz S B R Diagram shows a meterbridge wire AB has uniform cross sectional area and length L M is mid point of wire AB Resistivity of wire AM is p and that of MB is 2p Steady current is flowing in circuit It is observed that when jocke touches mid point of wire AM then deflection in galvanometer is zero Find ratio of resistance S and R

4 0 Consider the following circuit Battery is ideal Choose current statement s Current passing through all three resistors is same Current passing through battery is 4 Amperes Potential difference across all resistors is same Thermal power dissipated in 62 resistor is half of the power supplied by battery 302 www www 652 12 Volt 352

1 2 3 4 rect Answer 3 Answer 4 us incorrect Thermo couple Radiator Resistor Generator add to Bookmark List Feel statt 5 Onattempted 10 7 Correct 09 0 incorrect s

Find The amount of charge that flows through the switch S in C Assume the capacitors are uncharged before connecting in the circuit 4 F 2 F 50 V S 2 F 4 F

Consider the circuit shown in the diagram Current passing through wire AB is 6 ampere Potential difference across two batteries is different O Potential difference across two batteries is same O Power supplied by both batteries is same 6 volt Hint 202 A 122 B option in this 4 volt 152

atsApp Image 2021 04 16 at 10 2554 AM jpeg 252 11 Find the currents in the different resistors shown in figure 32 W5 202 2V O 402 2 2VT X 2 V 852 www 802 EN

70 For what value of the length the deflection in the galvanometer will be zero in the following potentiometer arrangement The length of the wire AB is 4 m and its resistance is 10 9 A 1 0 8 m 2 1 6 m 3 2 4 m 4 3 6 m 0 5 A All 2V G w B

4 70 F capacitor that is initially uncharged is onnected in series with a 5 00 k2 resistor and an emf source with E 150 V negligible internal esistance Part A Just after the circuit is completed what is the voltage drop across the cap AEO 6 A G 102 2

Source O Bulb In the figure a bulb of 25W is used The power dissipated in the wires connecting the bulb to source is 2mW If a bulb of 100W is used what will be the approx Power dissipated in wires SolveLancer Test a 32mW b 4mW c 16mW d 2mW

c 2 4 x 10 9 26 The electrostatic attracting force on a small sphered charge 0 2 C due to another small sphere of charge 0 4 C in air is 0 4 N The distance between the two spheres is a 43 2 x 10 6 m c 18 1 x 10 m b 42 4 x 10 m d 19 2 x 10 m

5 AB is a uniform wire of length 70 cm and resistance 702 Part AC is 20 cm long Two resistors and two idea cells are connected as shown A 2V 1 502 C 1V 20 Potential gradient of the part CB of the wire is A 2 5V m 10 C V m 3 B B 2V m D 7 5V m

The network of resistance connected across the cell shown in the diagram is infinitely long The cell is ideal 6V 10 252 12 m 202 w 10 2025 10 4 The maximum potential difference across any of the 19 resistors is A I V B 2 V C 3 V 202 D 4 V 14 22

11 A polythene piece rubbed with wool is found to have a negative charge of 6 x 10 7 C The number of electrons transferred to polythene from wool is a 3 75 x 1010 c 9 6 x 10 2 b 9 6 x 10 0 d 3 75 x 10 2 du

c 9 6 x 10 2 d 3 75 x 10 2 2 If 10 electrons move out of a body to another body every second then the time required to get a total charge of 1 C on the other body is a 250 years c 198 years b 100 years d 150 years

4 9 A I and mass m is placed along the east west line on a table Suddenly a certain amount of charge is passed through it and it is found to jump to a height h The earth s horizontal magnetic induction is B The charge passed through the conductor is 1 A Bmgh C gh Blm B 2gh Blm m 2gh Bl ading R with a

22 Figure shows rough sketch of meter bridge Galvanometer G deflects zero at length cm Now R and R are interchanged then balancing length increases by 25 cm The ratio R R is equal to 180 1 3 3 5 2 1000 a R 2 4 R 2 5 5 2 f sq 180

S resistors each of resistance R are connected as shown in the figure R D C A R R www 1170 R The equivalent resistance between A and C is 2R 5 The equivalent resistance between A and B is 8R 15 The equivalent resistance between B and O is 7R 15 The equivalent resistance between B and D is 2R 3 R www R R B

24 For the circuit given below the Kirchoff s loop rule fort he loop BCDEB is given by the equation Ai B 1 C E R wwwwww R www F E a i R E E i R 0 b iR E E3 1 R 0 c 1 R E E3 i R 0 2 E d i R E E i R 0 d 2 1 D E 28 n

In the circuit shown determine the equivalent resistance total current and power in each resistor if the supply voltage between terminals A and B is 440 Volts A 400 52 B 1000 2 ww 500 Q ww 300 2 600 22 406 10022 50 W

Example 3 38 In the circuit shown in figure E 10V E 4V 1 1 2 122 and R 202 Find the potential difference across battery 1 and battery E r m E tim T2 Ex

Three resistances 102 202 and 302 are connected in parallel The ratio of current passing through them when a p d is applied across thhe ends is 1 2 3 6 2 1 2 3 3 1 1 1 4 6 3 2

For a ccell the graph between the p d v across the terminals of the cells and the current I drawn from the cell as shown The emf annd internall resistance is V 2 in volt 0 Iin amp 3

A circuit involving five ideal cells three resistance R R and 2002 and a capacitor of capacitance C 1 F is shown Match the conditions in Column l with results given in Column II Assuming circuit is in steady state A B C D F30V 2002 K Column I K is open and K is in position C K is open and K is in position D K is closed and K is in position C K is closed and K is in position D 10V HH C 1uF R 20V B K 12V 14V Column II P Potential at point A is greater than potential at B Q Current through R is downward R Current through R is upward S Charge on capacitor is 20 C T Charge on capacitor is 10 C

An electric bell has a resistance of 552 and requires a current of 0 25 A to work it Assuming that the resistance of the bell wire is 192 per 15m and that the bell push is 90m distance from the bell How many cells each of emf 1 4V and internal resistance 202 will be required to work the circuit A 3 B 4 C 5 D Can t be determined

Two cells of emf 1V 2V and each of internal resistance1 are connected in parallel with their unlike terminals connected together to form a battery A resistance of 1 5 is connected in series with the battery Current through external resistance is A 0 5A B 0 25A C 1A D 0 75A

Q 2 Study the circuit shown in which three identical bulbs B B and B are connected in parallel with a battery of 4 5 V a What will happen to the glow of other two bulbs if the bulb B gets fused 1 b If the wattage of each bulb is 1 5 W how much readings will the ammeter A show when all the three bulbs glow simultaneously 1 c Find the total resistance of the circuit 1 A 4 5 V Ba d How many resistors of 88 W are connected in parallel to carry 10 A current on a 220 V line

A certain solar cell type has an output capability of 0 5 Amp at 0 9 V A series parallel solar array has been designed of such cells with 166 parallel strings and each string has 109 cells in series Current capability of array in Amperes h

64 Two identical heaters marked 1000W 250V are placed in series with each other and with a supply of 250 volt Their combined rate of heating assuming their resistances stay constant will be a 250W c 1000W b 500W d 2000W

E 5 An electric bell has a resistance of 50 and requires a current of 0 25 A to work it Assuming that th resistance of the bell wire is 192 per 15m and that the bell push is 90m distance from the bell Ho many cells each of emf 1 4V and internal resistance 202 will be required to work the circuit D Can t be determined A 3 B 4 CEO C 5