# Current Electricity Questions and Answers

Physics
Current Electricity
resistance Explain which one of the two wires is thicker 2 b If current flowing in a copper wire is allowed to flow through an iron wire of same thickness then explain how drift velocity will change 2 c In a Potentiometer setup experiment on meter bridge AB if the balancing length
Physics
Current Electricity
A 54 5 V 3 52 B 3 5 V 54 50 C 11V 2 32 D 3V 5402 A 102 resistor is rated capable of dissipating 5W The maximum current the resistor can tolerate A 0 5A B 0 707A C 1 414A D 1 A A p d of 100V is applied across a copper wire of length 1m The average drift
Physics
Current Electricity
In a potentiometer circuit two wires of same material of resistivity one of radius of cross section a other of radius of cross section 2a are joined in series They are of length L 2L respectively This combination acts as the potentiometer wire of length 3L The emf of the cell in the primary circuit is e internal resistance is pl 27a This cell is connected to the potentiometer wire by a conducting wire of negligible resistance with positive terminal of the cell connected to one end call it A of longer wire Find the balancing length measured from point A obtained in measurement of emf of cell of emf 2 L OL 2 2L 5
Physics
Current Electricity
water A resistor of resistance R carries a variable current The current decreases with time continuously such that its value becomes half after every 5s Starting from t 0 the total charge which passes through the res by the time current becomes zero is Q The time from the beginning in which the half the total charge passed through the resistor R is in s
Physics
Current Electricity
under the condition of 15 Inductive time constant for the given L R circuit is 16 mH oooo 160 88762 42 16 2 wwww 6 V www 16 02 422 www 1 ms 2 3 ms 3 4 ms 4 8 ms 5 A convex lens and a convex mirror of focal lengt
Physics
Current Electricity
Carbon resistor has resistance specified by three bands having colour red yellow and black If this resistor is cut into two pieces of equal length then the new colour code of each one will be Neglect tolerance of 4th band Brown Red Black Red Orange Black White Blue Black O Black Blue Black
Physics
Current Electricity
The electric potential changes from 10 V to 30 V as one moves along x axis from x 0 to x 2 m The magnitude of electric field in the region Must be 10 V m May be 10 V m May be 20 V m Both 2 and 3
Physics
Current Electricity
Two wires of same material length 2 and area of cross section A and 2A respectively are connected is series to cell The ratio of potential drops across the resistance wires are 24 012 021 04 1 01 4
Physics
Current Electricity
A solenoid resistance battery Time taken for the magnetic energy reach 1 4 th of its maximum value has an inductance of 10 henry and of 2 Q It is connected to a 10 approximately 1 2 s 3 3 5 s 2 8 s 4 2 5 s A
Physics
Current Electricity
22 Consider the situation as shown in the figure The work done in taking a point charge from point P to A is WA from P to B is WB and from P to C is Wc then q A 1 WA WB Wc 2 WA WB Wc 3 WA WB Wc B C p P JA PIB
Physics
Current Electricity
3 A wire of length L and 3 identical cells of negligible internal resistances are connected in series Due to the current the temperature of the wire is raised by AT in time t N number of similar cells is now connected in series with a wire of the same material and cross section but of length 2L The temperature of the wire is raised by the same amount AT in the same time t The value of N is A 4 B 6 C 8 D 9 A O B C
Physics
Current Electricity
The ammeter A reads 4 A and the voltmeter Vreads 40 V The value of resistance Ris Assuming finite value of resistance of ammeter and voltmeter R Exactly 10 ohm O Less than 10 ohm O More than 10 ohm View Information insufficient
Physics
Current Electricity
In a circuit shown in figure the heat produced in 50 resistor due to current flowing in it is 20 J The heat produced in 60 resistor is 402 www 12 J OBJ 602 www www 592
Physics
Current Electricity
View in Engilah Ten cell each of emf E and same internal resistance rare connected in series If due to oversight one cell is connected wrongly then the equivalent e m f of the combination is O 12 E O 10 E O BE O BE
Physics
Current Electricity
View in English In a meter bridge the balancing length from the left end standard resistance of two ohm is in the right gap is found to be 40 cm The value of unknown resistance is O 40 O 47 C 3 O 20
Physics
Current Electricity
View in English Three identical bulbs are connected as shown in figure When switch S is open the power consumed in the bulb A is P what is the power consumed by the same bulb when switch S is closed A vo O 9P 4 B
Physics
Current Electricity
Q 5 The battery in the diagram is to be charged by the generator G The generator has a terminal voltage of 120 volts when the charging current is 10 amperes The battery has an emf of 100 volts and an internal resistance of 1 ohm In order to charge the battery at 10 amperes charging current the resistance R should be set at A 0 192 B 0 502 C 1 0 2 D 5 0 2 O A OB O c www AF 100 V 12
Physics
Current Electricity
Q 12 By error a student places moving coil voltmeter V nearly ideal in series with the resistance in a circuit in order to read the current as shown The voltmeter reading will be A 0 O A OB O c C B 4V C 6V E 12V r 202 492 D 12V V
Physics
Current Electricity
View in English Three resistance P Q Reach of 30 and an unknown resistance Sform the four arms of a wheatstone bridge circuit When a resistance of 6 Q is connected in parallel to S the bridge get balanced What is value of S 0 60 0 40 9 30
Physics
Current Electricity
View in English A potentiometer consists of a wire of length 8 m and resistance 20 Q It is connected to a cell of e m f 4 V The potential difference per unit length of the wire will O 4 V m O 1 V m O 0 5 V m O 5 V m
Physics
Current Electricity
Q 2 Two batteries one of the emf 3V internal resistance 1 ohm and the other of emf 15 V internal resistance 2 ohm are connected in series with a resistance R as shown If the potential difference between a and b is zero the resistance of R in ohm is A 5 B 7 C 3 D 1 O A O B O c C C 3V 10 15V 202 R
Physics
Current Electricity
Q 11 In the circuit shown the resistances are given in ohms and the battery is assumed ideal with emf equal to 3 0 volts The resistor that dissipates the most power is A R B R C R D R O A O B O C 3V 50 2 ww R R 600 R 50 02 R 30
Physics
Current Electricity
Q 17 If X Y and Z in figure are identical lamps which of the following changes to the brightnesses of the lamps occur when switch S is closed O O O A X stays the same Y decreases C X increases Y stays the same O A OB O C B X increases Y decreases D X decreases Y increases
Physics
Current Electricity
Two cells of emf E and E2 are joined in series and the balancing length of potentiometer wire 550 cm If the terminal of E is reversed the balance length obtained is 150 E cm Given E E the ratio will be O 2 3 O 317
Physics
Current Electricity
Q 13 A storage battery is connected to a charger for charging with a voltage of 12 5Volts The internal resistance of the storage battery is 192 When the charging current is 0 5 A the emf of the storage battery is A 13 Volts B 12 5 Volts C 12 Volts D 11 5 Volts O O O O A B O C
Physics
Current Electricity
O A body cools from a temperature 3T to 2T in 10 minutes The room temperature s T Assume that average method of Newton s law of cooling is applicable The emperature of the body at the end of next 10 minutes will be O O 7T 4 3T Read More 4T 3 questions Out of these 15 questions
Physics
Current Electricity
Resistance of 6 Q each are connected as shown in diagram when the current 1 A is flowing as shown The potential difference Vp Vois 6 52 692 692 www 602 www 692 O 3 V O 6V 09V Read More 602 www
Physics
Current Electricity
105 In given circuit the power consumed in 120 16 resistor is W then the power consumed in 3 49 resistan is A 64 3 W 16 85 www 452 ww 120 ww 120 B 64 9 16 W W
Physics
Current Electricity
13 A coil having n turns and area A is initially placed with its plane normal to the magnetic field B It is then rotated through 1800 in 0 2 sec The emf induced at the ends of the coils is A 0 1 nAB C 5 nAB B nAB D 10 nAB 120
Physics
Current Electricity
This section contains 35 SINGLE CORRE YPE questions Each question has 4 Read More The current in the part of electric circuit is 1 A 2A 12A 01 A O 1 7 A O 2 5 A R 1 1 3 A
Physics
Current Electricity
In the circuit shown R 9 Q R 2 30 Q R 3 15 Q2 and the emfs 1 29 V 2 10 V and 3 15 V Calculate 13 Your result must be in Amperes and include 2 digit after the decimal point Maximum of 5 of error is accepted in your answer 1 R ww 1 E3 T
Physics
Current Electricity
20 Equipotential surfaces are shown in the region in x plane Electric field intensity in the region is 1 50 2 50 3 50 4 50 m M 3 V 30 10 V 15 V 20 V 20 cm 40 cm 120 from ve x axis 60 from ve x axis 30 from ve x axis 150 from ve x axis X
Physics
Current Electricity
For a metallic conductor if p is resistivity at T and po is resistivity at reference temperature To then resistivity p is given by a is temperatu coefficient of resistivity 0 NCERT Pg 10 1 PT Po 1 T To 2 PT Po 1 a T To 3 PT Po 1 To T 4 T P 1 a T T
Physics
Current Electricity
The radius of cross section of the conductor of length varies linearly from a to 2a If the resistivity of the conductor is p and a the resistance of the conductor will be 0 pl 2 a 2p 5na na pl 2a
Physics
Current Electricity
Potentiometer can be used to measure emf of any cell more effectively than voltmeter because OIt works on deflection method OIt use a large current to measure emf OIt draws no current from cell while measuring its emf OIt is based on Wheatstone bridge
Physics
Current Electricity
View in English A 2 V potentiometer is used to determine the internal resistance of a 1 5 V cell the balance point of the cell in the open circuit is 75 cm When a resistor of 10 Q is connected across the cell the balance point shifts to 60 cm The internal resistance of the cell is O 1 50 O 250 350 O 4 50
Physics
Current Electricity
In the given figure a circuit is shown In this figure galvanometer G will have zero deflection only wh P www OPQ RS OPR QS OPS QR www S www For any relation between rocictonco
Physics
Current Electricity
In figure current in the wire between a and b is neglect any resistance of connecting wires E r E r 1 E r 3 3E 4r b E r a BIN 2 5E 4r 4 E 2r
Physics
Current Electricity
View in English When the switch is open in lowermost loop secondary circuit of a potentiometer the balance point length is 60 cm When the switch is closed with a known resistance of R 4 ohm the balance point length decreases to 40 cm Find the internal resistance of the unknown battery 40 O20 O30
Physics
Current Electricity
Five equal resistances each of connected as shown in the Figure A battery of V volts is connected between A and B The current flowing in AFCEB will be A VR 2 V D R R C R F www A www R B B B E D V 2 R 3 V
Physics
Current Electricity
The V I graph for a conductor at temperature T and T is shown in the figure T T is proportional to V fag T T 1 T T K A cos20 B sin20 C cot20 D tan20 Your Answer
Physics
Current Electricity
Two electric bulbs A and B are rated as 60W and 100W If they are connected in parallel to the same source then AB 60 100 DA GA S CAR A Both the bulbs draw the same current GHIA VIRI yafed m B Bulb A draws more current than the bulb B C A B Bulb B draws more current than the bulb A BRA D Currents drawn by the bulls are in the ratio of their resistances fu
Physics
Current Electricity
In the figure two cells have equal emf E but internal resistance are r and r If the reading of voltmeter is zero then the relation between R r and r is vai fax emffem arafer var ar af alcenter an www A R 1 1 B R 1 1 C 2R 1 1 D R Your Answer
Physics
Current Electricity
4 For a black body at temperature 727 C its radiating power is 60 watt and temperature of surrounding is 227 C If temperature of black body is changed to 1227 C then its radiating power will be AIPMT 2002 1 304 W 2 320 W 3 240 W 4 120 W lon oxpress relation between AIPMT 2002
Physics
Current Electricity
and the emf of its standard cell is E volt It is employed to measure the emf of a battery whose internal resistance is 0 5 22 If the balance point is obtained at 30 cm from the positive end the emf of battery is 30 E 100 5 30 E 100 0 5 30 E 0 51 100 potentiometer wire 30 F 1 where i is the current in the
Physics
Current Electricity
Q3 A car has a fresh battery of emf 12V and internal resistance 0 050 If the starter motor draws a current of 90A the terminal voltage when the starter is on will be O A 10 5V O B 7 5V O C 2 5V O D 12V
Physics
Current Electricity
A network is arranged as in Mance s experiment This is used to find the internal resistance of the battery R The resistance of galvanometer and of each of the other three arms is 4 ohms The current in the galvanometer with the key open as well as when it is closed is 0 2A The internal resistance of battery is www B A 402 C 80 S K R A B 20 D 10
Physics
Current Electricity
2 Ad 2 d 20 E d The voltage drop across a capacitor connected with a resistance and a battery of 60 V in series after a long time is 1 0 V 2 60 V 3 30 V 4 38 V AIIMS 2012 A 400 DF capacitor is charged with a 100 V battery After disconnecting the battery this capacitor is connected with JAIIMS 2013
Physics
Current Electricity
What would be the voltage across C 1 C C V 2 C V C C C Cy V 3 C V C C C AIIMS 20 C V 4 C C C
Physics
Current Electricity
A letter A consists of a uniform wire of resistance 0 2 oh m per cm The sides of the letter are each 20 cm long and the cross piece in the middle is 10 cm long while the apex angle is 60 degree Find the resistance of the letter betwe en the two ends of the legs