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What is the internal resistance of the cell if the e.m.f. of the cell is 2.08volt and the terminal potential of the cell is 2.00 volt when a 2  resistance is connected?
 

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Important Questions on Current Electricity

EASY

The figure shows a part of a closed circuit. If the current flowing through it is 2 A then VB-VA is _______

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EASY
Two sources of equal emfs are connected in series. This combination is connected to an external resistance R. The internal resistances of the two sources are r1 and r2r1>r2. If the potential difference across the source of internal resistance r1 is zero then the value of R will be
MEDIUM
Two identical cells each of emf 1.5 V are connected in parallel across a parallel combination of two resistors each of resistance 20 Ω. A voltmeter connected in the circuit measures 1.2 V. The internal resistance of each cell is :
MEDIUM
Two cells of emf 6V and 3V of internal resistances 1Ω and 2Ω respectively are connected in parallel with their positive terminals together and similarly the negative terminals together. The equivalent emf of the combination would be
EASY
A cell of emf 1.8 volts gives a current of 17 A when directly connected to an ammeter of resistance 0.06 Ω. Internal resistance of the cell is
MEDIUM
Two cells of internal resistances r1 and r2 and of the same emf are connected in series, across a resistor of resistance R. If the terminal potential difference across the cells of internal resistance r1 is zero, then the value of R is
MEDIUM
A cell of emf 4 V and internal resistance 0.2 Ω is connected with the resistance of 1.8 Ω. The voltage across the cell terminal will be
MEDIUM
Internal resistance of a cell is independent of
MEDIUM

When an ammeter of negligible internal resistance is inserted in series with the circuit, it reads 1 A. When a voltmeter of very large resistance is connected across R1, it reads 3 V. But when the points A and B are short-circuited by a conducting wire, then the voltmeter measures 10.5 V across the battery. The internal resistance of the battery is equal to
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MEDIUM
Find the emf induced in the coil shown in figure. if the magnetic field is perpendicular to the coil and is constant.

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EASY

The internal resistances of two cells shown are 0.1 Ω and 0.3 Ω. If R=0.2 Ω, the potential difference across the cell

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HARD

A voltmeter having a resistance of 1800 Ω is employed to measure the potential difference across 200 Ω resistance, which is connected to dc power supply of 50 V and internal resistance 20 Ω. What is the approximate percentage change in the potential difference across 200 Ω resistance as a result of connecting the voltmeter across it?

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MEDIUM
A wire 88 cm long bent into a circular loop is placed perpendicular to the magnetic field of flux density 2.5 Wb m-2. Within 0.5 s, the loop is changed into a square and flux density is increased to 3.0 Wb m-2 . The value of e.m.f. induced is :
MEDIUM
In the given circuit the reading of the ideal voltmeter is E2. The internal resistance of the battery is
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HARD
In the circuit shown A and B are two cells of same emf E, but different internal resistances r1 and r2 (r1>r2), respectively. What is the value of R in terms of r1 and r2, such that the potential difference across the terminal of cell A is zero a long time after the key K is closed.

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EASY
Two cells of equal EMF and of internal resistances r1 and r2 r1>r2 are connected in series. On connecting this combination to an external resistance R, it is observed that the potential difference across the first cell becomes zero. The value of R will be
EASY
A battery having e.m.f. 5 V and internal resistance 0.5 Ω is connected with a resistance of 4.5 Ω then the voltage at the terminals of battery is
EASY

The reading on a high resistance voltmeter, when a cell is connected across it, is 2.0V. When the terminals of the cell are also connected to a resistance of  3 Ω  as shown in the circuit, the voltmeter reading drops to 1.5V. The internal resistance of the cell is :

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HARD
A cell of emf E is connected across a resistance R. The potential difference between the terminals of the cell is found to be V. The internal resistance of the cell must be -
EASY

A battery has an emf of 15 V and internal resistance of 1 Ω . The terminal to terminal potential difference is less than, equal to or greater than 15 V, if the current in the battery is

(1) from negative to positive terminal,

(2) from positive to negative terminal,

(3) zero current?