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
1.
2.
3.
4.
In the circuit shown in the figure, the current supplied by the battery is
1. 2A
2. 1A
3. 0.5A
4. 0.4A
If a resistance coil is made by joining in parallel two resistances each of 20. An emf of 2V is applied across this coil for 100 seconds. The heat produced in the coil is
(1) 20 J
(2) 10 J
(3) 40 J
(4) 80 J
1.
2.
3.
4.
The equivalent resistance across AB is :
1. 2R
2. R/2
3. 4R/3
4. 3R/2
The equivalent resistance between points A and B in the circuit shown in the figure is
1. 6R
2. 4R
3. 2R
4. R
In the circuit shown in the figure, the effective resistance between A and B is:
1. 2
2. 4
3. 6
4. 8
For the circuit shown in the figure, the value of R must be
1. 3
2. 4
3. 5
4. 6
The current I as shown in the circuit will be:
1. 10 A
2.
3.
4.
The current through the 5 resistor is:
1. 3.2 A
2. 2.8 A
3. 0.8 A
4. 0.2 A
The equivalent resistance of the following infinite network of resistances is
(1) Less than 4 Ω
(2) 4 Ω
(3) More than 4 Ω but less than 12 Ω
(4) 12 Ω
What is the current (i) in the circuit as shown in figure
(1) 2 A
(2) 1.2 A
(3) 1 A
(4) 0.5 A
In the given figure, the equivalent resistance between the points A and B is :
(1) 8 Ω
(2) 6 Ω
(3) 4 Ω
(4) 2 Ω
Effective resistance between A and B is :
(1) 15 Ω
(2) 5 Ω
(3)
(4) 20 Ω
In the circuit shown in the adjoining figure, the current between B and D is zero, the unknown resistance is of
(1) 4 Ω
(2) 2 Ω
(3) 3 Ω
(4) em.f. of a cell is required to find the value of X
The current in the given circuit is
(1) 0.1 A
(2) 0.2 A
(3) 0.3 A
(4) 0.4 A
Eels are able to generate current with biological cells called electroplaques. The electroplaques in an eel are arranged in 100 rows, each row stretching horizontally along the body of the fish containing 5000 electroplaques. The arrangement is suggestively shown below. Each electroplaques has an emf of 0.15 V and internal resistance of 0.25 Ω
The water surrounding the eel completes a circuit between the head and its tail. If the water surrounding it has a resistance of 500 Ω, the current an eel can produce in water is about
(1) 1.5 A
(2) 3.0 A
(3) 15 A
(4) 30 A
A potentiometer is an accurate and versatile device to make electrical measurement of EMF because the method involves
1. cells
2. potential gradients
3. a condition of no current flow through the galvanometer
4. a combination of cells, galvanometer, and resistances
The potential difference between points A and B in the given figure is if the current is flowing from A to B:
(1) - 3 V
(2) +3 V
(3) +6 V
(4) +9 V
A potentiometer wire is 100 cm long and a constant potential is maintained across it. Two cells are connected in series first to support one another and then in the opposite direction. The balance points are obtained at 50 cm and 10 cm from the positive end of the wire in the two cases. The ratio of emf is
1. 5:4 2. 3:4
3. 3:2 4. 5:1
The charge following through a resistance R varies with time where a and b are positive constants. The total heat produced in R is
(1)
(2)
(3)
(4)
A potentiometer wire has a length 4 m and resistance 8Ω. The resistance that must be connected in series with the wire and an accumulator of emf 2V, so as to get a potential gradient 1mV per cm of the wire is
(1)32Ω
(2)40Ω
(3)44Ω
(4)48Ω
A, B, and C are voltmeters of resistance R, 1.5R, and 3R respectively as shown in the figure. When some potential difference is applied between X and Y, the voltmeter readings are VA, VB, and VC respectively. Then,
1. VA=VB=VC
2. VA≠VB=VC
3. VA=VB≠VC
4. VA≠VB≠VC
A potentiometer wire of length L and a resistance r are connected in series with a battery of e.m.f. and a resistance r1. An unknown e.m.f. is balanced at a length l of the potentiometer wire. The e.m.f. E will be given by
(1)
(2)
(3)Eol/L
(4)
Two cities are 150 km apart. Electric power is sent from one city to another city through copper wires. The fall of potential per km is 8V and the average resistance per km is 0.5 Ω. The power loss in the wire is
(1) 19.2W
(2) 19.2kW
(3) 19.2J
(4) 12.2kW
A potentiometer circuit has been setup for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance, R, connected across the given cell, has values of
(i)infinity
(ii)9.5Ω
the 'balancing lengths', on the potentiometer wire are found to be 3m and 2.85m, respectively. The value of internal resistance of the cell is
(1) 0.25Ω
(2) 0.95Ω
(3) 0.5Ω
(4) 0.75Ω
In the circuit shown the cells A and B have negligible resistances. For the galvanometer (g) shown no deflection.The value of is
(a)4V (b)2V
(c)12V (d)6V
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
(1)20%
(2)2.5%
(3)5%
(4)10%
A ring is made of a wire having a resistane
. Find the points A and B, as shown
in the figure, at which a current carrying
conductor should be connected so that the
resistance R of the sub circuit between these
points is equal to 8/3
1. 2.
3. 4.
The power dissipated in the circuit shown in
the figure is 30 Watt. The value of R is :
(1)
(2)
(3)
(4)
If power dissipated in the 9 resistor in the circuit
shown is 36 W, the potential difference across
the 2 resistor is
(a) 8 V
(b) 10 V
(c) 2 V
(d) 4 V
In the circuit in the figure, if the potential at point A is taken to be zero, the potential at point B is :
1. -1V 2. +2V
3. -2V 4. +1V
A potentiometer circuit is set up as shown.The potential gradient across the potentiometer wire, is k volt/cm and the ammeter, present in the circuit, reads 1.0A when two way key is switched off. The balance points, when the key between the terminals (i) 1 and 2 (ii) 1and 3, is plugged in, are found to be at lengths respectively.The magnitudes, of the resistors R and X, in ohm, are then, equal, respectively, to
(a)
(b)
(c)
(d)
A wire of resistance is bent to form a complete circle of radius 10 cm. The resistance between its two diametrically opposite points, A and B as shown in the figure, is :
(a) (b)
(c) (d)
See the electrical circuit shown in this figure. Which of the following equation is a correct equation for it?
1.
2.
3.
4.
A current of 3A flows through the 2 resistor shown in the circuit. The power dissipated in the resistor is
(a) 4 W (b) 2 W
(c) 1 W (d) 5 W
A wire of a certain material is streched slowly by ten per cent. Its new resistance and specific resistance become respectively
(1) 1.2 times, 1.1 times
(2) 1.21 times,same
(3) both remain the same
(4) 1.1 times, 1.1 times
An electric kettle takes 4 A current at 220 V. How much time will it take to boil 1 kg of water from temperature C? The temperature of boiling water is C
(a) 6.3 min
(b) 8.4 min
(c) 12.6 min
(d) 4.2 min
A cell can be balanced against 110cm and 100 cm of potentiometer wire, respectively with and without being short-circuited through a resistance of . Its internal resistance is
(1) 1.0
(2) 0.5
(3) 2.0
(4) zero
In the circuit shown, the current through the 4 resistor is 1 A when the points P and M are connected to a DC voltage source. The potential difference between the points M and N is
1. 1.5 V
2. 1.0 V
3. 0.5 V
4. 3.2 V
A milliammeter of range 10 mA and resistance 9 is joined in a circuit as shown in Fig. 6.57. The meter gives full-scale deflection for current I when A and C are used as its terminals if current enter at A and leaves at C (B is left isolated). The value of I is :
(1)100 mA
(2) 900 mA
(3) 1 A
(4) 1.1 A
A candidate connects a moving coil voltmeter V, a moving coil ammeter A, and a resistor R as shown in Fig. 6.58. If the voltmeter reads 20 V and the ammeter reads 4 A, R is
(1) equal to 5
(2) greater than 5
(3) less than 5
(4) greater or less than 5 depending upon its material.
A voltmeter has a resistance of G ohm and range V volts. The value of resistance used in series to convert it into a voltmeter of range nV volts is :
(1) nG
(2) (n-1)G
(3) G/n
(4) G/(n-1)
A galvanometer has a resistance of 3663 . A shunt S is connected across it such that 1/34 of the total current passes through the galvanometer. The value of the shunt is :
(1) 3663
(2) 111
(3) 107.7
(4) 3555.3