Q.1
A cell of e.m.f E and internal resistance r has an external resistance R connected across it. IF the terminal potential difference across the terminals of the cell is V, then
  • a)r=R
  • b) r=R(E/V)
  • c)r=R(E-V)/V
  • d)r=RV/E
Q.2
A capacitor of 10µF ha a potential difference of 40 V across it. If it is discharged in 0.2s, the average current during discharge is
  • a) 2 mA
  • b) 4 mA
  • c)1 mA
  • d)0.5 mA
Q.3
An external resistance R is connected to a cell of emf E and internal resistance r. Maximum power delivered to R is
  • a) E2 / r
  • b) E2 / 2r
  • c) E2 / 4r
  • d) E2 / 8r
Q.4
An external resistance R is connected to a cell of emf E and internal resistance r., the terminal potential difference is zero, when
  • a) R > r
  • b) R=r
  • c) R=0
  • d) R=∞
Q.5
The resistance of the circuit between A and B is ( each resistance is o r
ch-14_que_no-265_img_no1.png
  • a)r
  • b) 0.5r
  • c)2r
  • d)3r
Q.6
A battery of 20 cells is charged by 220V with a charging current of 15 ampere. If the e.m.f of each cell is 2 V and internal resistance is 0.1 Ω, then the series resistance required to be placed in the circuit is
  • a) 12 Ω
  • b) 14 Ω
  • c)10 Ω
  • d)16 Ω
Q.7
In above problem amount of power wasted as heat is
  • a) 450 watt
  • b) 3300 watts
  • c)2700 watt
  • d)2250 watt
Q.8
The resistance of the circuit between the points A and B is
ch-14_que_no-268_img_no1.png
  • a) R
  • b) 8R/3
  • c) 4R/3
  • d) cannot be calculated
Q.9
The length of a potentiometer wire required to balance the e.m.f of cell A is 60 cm. The length of the wire under the same conditions required to balance the e.m.f. if cll B is 45 Cm. If the e.m.f. of the cell B is 3.0 V, the e.m.f. of the cell A is
  • a)2.25 V
  • b) 2.5 V
  • c)4.0 V
  • d)4.5 V
Q.10
Five cells, each of e.m.f E and internal resistance r are connected in series. If due to oversight, one cell is connected wrongly, then the equivalent e.m.f. and internal resistance of combination is
  • a) 5E and 5r
  • b) 3E and 3r
  • c)3E and 5r
  • d)5E and 3r
Q.11
In figure , AB is a potentiometer wire of length 10m and resistance 2Ω. With key k open the balancing length is 5.5 m. However on closing key k the balancing length reduces to 5 m. The internal resistance of the cell E1 is :
ch-14_que_no-271_img_no1.png
  • a)0.01 Ω
  • b) 0.1 Ω
  • c)0.2 Ω
  • d)1.0Ω
Q.12
In figure, AB is potentiometer wire of length 10 m and resistance 1Ω. The balancing length for 2 volt p.d. is 8m. The emf of the battery E is
ch-14_que_no-272_img_no1.png
  • a) 2.75 V
  • b) 13.75 V
  • c) 27.5 V
  • d) 5.5 V
Q.13
Four identical cells each having emf E, internal resistance zero are connected as shown in figure. The potential difference between A and B is :
ch-14_que_no-274_img_no1.png
  • a) 4E
  • b) 2E
  • c)E
  • d)zero
Q.14
In a potentiometer experiment, it is found that no current flows through the galvanometer when the terminals of the cells are connected across 52 cm of the potentiometer wire. If cell is shunted by a resistance of 5Ω a balance is found when the cell is connected across 40 cms of the wire. the internal resistance of the cell is
  • a) 5 Ω
  • b) (200/52) Ω
  • c) (52/8) Ω
  • d) 1.5 Ω
Q.15
A short piece of iron wire glows red hot when placed across the terminals of a2 volts accumulator ( storage battery), but the same piece of wire does not get worm when connected across the terminals of 9 volt 'dry' battery. This is because
  • a) the dry battery is smaller
  • b) the dry battery does not contain enough electric charges
  • c) the wire makes better contact with accumulator
  • d) the dry battery has a high internal resistance
Q.16
In the circuit show below R1=10Ω, R2=20Ω, R3=30Ω and the potentials of points A, B and C are 10V, 6V and 5V respectively. The current through resistance R1 is :
ch-14_que_no-277_img_no1.png
  • a)0.1 A
  • b) 0.2 A
  • c)0.3 A
  • d)0.4 A
Q.17
In an electrolyte 3.2×1018 bivalent positive ions drift to the right per second while 3.6×1018 monovalent negative ions drift to left per second. Then the current is
  • a) 1.6 amp. to the left
  • b) 1.6 amp to the right
  • c)0.45 amp. to the left
  • d)0.45 amp to the right
Q.18
A cell of emf E and internal resistance r is connected in series with an external resistance nr. Then the ratio of the terminal potential difference to emf is
  • a) 1/n
  • b) 1 (n+1)
  • c)n/(n+1)
  • d)(n+1)/ n
Q.19
In comparing emf's of two cells with the help of a potentiometer, at the balance point the current flowing through the wire is taken from
  • a) one of these cells
  • b) both of these cells
  • c) the battery in the main circuit
  • d) none of above
Q.20
A number of cells are to be grouped so as to obtain maximum current. The internal resistance of each cell is r and the total external resistance is R. Which of the following is wrong?
  • a)Series combination for R >r and parallel for R < r
  • b) Series combination for R r
  • c)Mixed combination for R=r
  • d)None of the above
Q.21
Two dry cells P and Q have same emf. The dimensions of cells P are more than that of Q. r1 and r2 denotes internal resistance of P and Q respectively. Then
  • a) r1 and r 2
  • b) r1 > r 2
  • c)r1 < r 2
  • d)r1 and r 2 are unrelated to one another
Q.22
A battery is connected in series with an external resistance. The current in the circuit is 1A and 0.7 A when external resistance equals 5Ω and 8Ω respectively. The internal resistance of battery is
  • a) 0.2Ω
  • b) 0.5Ω
  • c)2Ω
  • d)0.6Ω
Q.23
In the circuit shown in the figure a voltmeter reads 30V when it is connected across 400Ω resistance. Calculate what the same voltmeter will read if it is connected across 300Ω resistance
ch-14_que_no-284_img_no1.png
  • a) 30 V
  • b) 60 V
  • c) 22.5 V
  • d) zero
Q.24
Figure represents a part of closed circuit. The potential difference between A and B i.e. VA - VB
ch-14_que_no-285_img_no1.png
  • a)24 V
  • b) 0 V
  • c)6 V
  • d)18 V
Q.25
A conductor contains 8×1022 free electrons per cubic metre. The conductor carries a current of 1A and has a length of 10cm. the are of cross section of the conductor is 7.81×the time taken by an electron to move from one end of the conductor to the other end is
  • a) 10-2s
  • b) 10-4 s
  • c)105 s
  • d)106
Q.26
In figure current in 3Ω and 6Ω resistance is
ch-14_que_no-287_img_no1.png
  • a)7.33A ; 3.67A
  • b) 3.67A; 7.33A
  • c)10.0A ; 15.0A
  • d)3.37A ; 6.74A
Q.27
The resistance in the left and right gap of a meter bridge are 3 Ω and 5Ω respectively. When resistance in the left gap increases by 10 percent, the balance point shifts by
  • a) 2.2 cm left
  • b) 22 cm left
  • c) 22 cm right
  • d) 2.2 cm right
Q.28
When resistance P and Q are kept in the left gap of a metre bridge the balance point is obtained at 40cm and 60 cm. respectively.When P and Q are connected in series in the same gap the balance point will be nearly at
  • a) 68.4 cm from left
  • b) 64.4 cm from right
  • c) 64.6 cm from left
  • d) 64.6 cm from right
Q.29
Potential gradient is defined as:
  • a) Fall of potential per unit length of the wire
  • b) Fall of potential per unit area of the wire
  • c) Fall of potential between two ends of the wire
  • d) Potential at any one ends of the wire
Q.30
Calculate the resistance between points P and Q in the circuit shown in the figure
ch-14_que_no-293_img_no1.png
  • a)7.5 Ω
  • b) 12 Ω
  • c)50 Ω
  • d)20 Ω
0 h : 0 m : 1 s