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The unknown resistance $R$ is measured using the circuit given. The meter resistance are $R_{v} = 10^{4} Ω$ (for the voltmeter) and $R_{A} = 2 Ω$ (for the ammeter) respectively. If the voltmeter reads $12 V$ and the ammeter reads $0.1 A$ , then

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Important Questions on Current Electricity

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

A uniform metallic wire has a resistance of

18 Ω

and is bent into an equilateral triangle. Then, the resistance between any two vertices of the triangle is:

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

A cell of

e . m . f . 10 V

and internal resistance

3 Ω

is connected to a resistor in series. If the current in the circuit is

0.5 A

, then find out the resistance of the resistor and terminal voltage across the cell.

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

E.M.F. of an electrical cell is

2 V

. A

10 Ω

resistance is joined at its two ends then the potential difference is measured

1.6 V

. Find the internal resistance and lost volt.

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

Equivalent resistance between points

A

and

B

in the adjacent circuit is

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MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

Write the relation of e.m.f of a cell and its internal resistance. What is the condition under which the potential difference between the terminals of the cell and its e.m.f are equal?

HARD

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

The figure shows three circuits

I, I I

and

I I I

which are connected to a

3 V

battery. If the powers dissipated by the configurations

I, I I

and

I I I

are

P_{1}, P_{2}

and

P_{3}

respectively, then -

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HARD

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

Obtain the expression for the effective emf and the effective internal resistance of two cells connected in parallel such that the currents are flowing in the same direction.

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

Space between two concentric conducting spheres of radii

a

and

b

(b > a)

is filled with a medium of resistivity

ρ

. The resistance between the two spheres will be:

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

Derive the expression for equivalent emf (

E_{eq}

) for the cells in series combination.

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

A resistor is connected across a cell of

emf 1.5 V

having an internal resistance of

1 Ω

. If a current of

200 mA

flows through the resistor, find the potential difference between the electrodes of the cell.

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

In a large building, there are 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and 1 heater of 1 kW. The voltage of the electric mains is 220 V. The minimum capacity of the main fuse of the building will be:

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

Two cells of the same EMF $E$ but different internal resistances $r_{1}$ and $r_{2}$ are connected in series with an external resistance $R$ as shown in the figure. The terminal potential difference across, the second cell is found to be zero. The external resistance $R$ must then be:

Question Image

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

Four bulbs

B_{1}

B_{2}

B_{3}

and

B_{4}

100 W

each are connected to

220 V

main as shown in the figure. The reading in an ideal ammeter will be

HARD

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

9 V

battery with an internal resistance of

0.5 Ω

is connected across an infinite network, as shown in the figure. All ammeters

A_{1}, A_{2}, A_{3}

and voltmeter

V

are ideal.
Choose the correct statement.

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

Six similar bulbs are connected as shown in the figure with a DC source of emf $E$ , and zero internal resistance.
The ratio of power consumption by the bulbs when $(i)$ all are glowing and $(ii)$ in the situation when two from section $A$ and one from section $B$ are glowing will be,
Question Image

HARD

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

A metal wire of resistance

3 Ω

is elongated to make a uniform wire of double its previous length. This new wire is now bent and the ends joined to make a circle. If two points on this circle make an angle

60^{o}

at the center, the equivalent resistance between these two points will be:

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

A wire of resistance

R

is bent to form a square

A B C D

as shown in the figure. The effective resistance between

E

and

C

is:
(

E

is mid-point of arm

C D

)

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

A battery of

e . m . f .

5 V

and internal resistance

2.0 Ω

is connected to an external resistance. If the current in the circuit is

0.4 A

, the terminal voltage of the battery is

EASY

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

A battery of e.m.f $12 V$ and internal resistance $0.5 Ω$ is charged by a battery charger which supplies a $132 V$ d.c. supply using a series resistance of $11.5 Ω$ . What is the terminal voltage of the battery during charging?

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Series and Parallel Arrangements of Resistances and Cells

A car has a fresh storage battery of e.m.f

12 V

and internal resistance

2 \times 10^{- 2} Ω

. If the starter motor draws current of

80 A

. Then the terminal voltage when the starter is on is

The unknown resistance R is measured using the circuit given. The meter resistance are Rv=104Ω (for the voltmeter) and RA=2Ω (for the ammeter) respectively. If the voltmeter reads 12V and the ammeter reads 0.1A, then

Important Questions on Current Electricity

Learn and Prepare for any exam you want !

The unknown resistance $R$ is measured using the circuit given. The meter resistance are $R_{v} = 10^{4} Ω$ (for the voltmeter) and $R_{A} = 2 Ω$ (for the ammeter) respectively. If the voltmeter reads $12 V$ and the ammeter reads $0.1 A$ , then