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Important Questions on Current Electricity

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

Resistance in the two gaps of a meter bridge are

10 Ω

and

30 Ω

, respectively. If the resistances are inter changed, the balance point shifts by

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

With a resistance of

X

in the left gap and a resistance of

9 Ω

in the right gap of meter bridge, the balance point is obtained at

40 cm

from the left end. In what way and to which resistance

3 Ω

resistance be connected to obtained the balance at

50 cm

from the left end?

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

In meter bridge experiment, to minimize an error due to contact resistance,

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

In a meter bridge as shown in the figure, it is given that resistance

Y = 12.5 Ω

and that the balance is obtained at a distance

39.5 cm

from end

A

(by jockey

J

). After interchanging the resistances

X

and

Y

a new balance point is found at a distance

l_{2}

from end

A

. What are the values of

X

(in

Ω

) and

l_{2}

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

During an experiment with a metre bridge, the galvanometer shows a null point when the jockey is pressed at $40.0 cm$ using a standard resistance of $90 Ω$ ,as shown in the figure. The least count of the scale used in the metre bridge is $1 mm$ . The unknown resistance is

Question Image

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

In a meter bridge when the resistance in the left gap is

2 Ω

and an unknown resistance in the right gap.the balance point is obtained at

40 cm

from zero end. On shunting, the unknown resistance with

2 Ω

, find the shift in the balance point.

EASY

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

A resistance wire connected in the left gap of a metre bridge balances a

10 Ω

resistance in the right gap at a point which divides the bridge wire in the ratio

3 : 2

. If the length of the resistance wire is

1.5 m

, then the length of

1 Ω

of the resistance wire is:

HARD

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

In a meter bridge, the wire of length $1 m$ has a non-uniform cross-section such that, the variation $\frac{d R}{d l}$ of its resistance $R$ with length $l$ is $\frac{d R}{d l} \propto \frac{1}{\sqrt{l}} .$ Two equal resistances are connected as shown in the figure. The galvanometer has zero deflection when the jockey is at point $P .$ What is the length $A P ?$

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MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

In a meter bridge experiment

S

is a standard resistance.

R

is a resistance wire. It is found that balancing length is

l = 25 c m .

R

is replaced by a wire of half length and half diameter that of

R

of same material, then the balancing distance

l'

(in

c m

) will now be ______________.
Question Image

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

In a meter bridge experiment, the circuit diagram and the corresponding observation table are shown in figure.
Question Image

S. No.	$R (Ω)$	$l (c m)$
_1. _2. _3. _4.	$1000$ $100$ $10$ $1$	$60$ $13$ $1.5$ $1.0$

Which of the reading is inconsistent?

EASY

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

The resistance in the two arms of the meter bridge are

5 Ω

and

R Ω,

respectively. When the resistance

R

is shunted with an equal resistance, the new balance point is at

1.6 l_{1} .

The resistance ‘

R

’ is:

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

In a meter bridge experiment resistances are connected as shown in the figure. Initially resistance

P = 4 Ω

and the neutral point

N

is at

60 cm

from

A

. Now an unknown resistance

R

is connected in series to

P

and the new position of the neutral point is at

80 cm

from

A

. The value of unknown resistance

R

is -

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

On interchanging the resistances, the balance point of a meter bridge shifts to the left by

10 cm

. The resistance of their series combination is

1 kΩ

. How much was the resistance on the left slot before interchanging the resistances?

HARD

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

Two unknown resistances are connected in two gaps of a meter-bridge. The null point is obtained at

40 cm

from left end. A

30 Ω

resistance is connected in series with the smaller of the two resistances, the null point shifts by

20 cm

to the right end. The value of smaller resistance in

Ω

EASY

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

Statement 1 : In post-office box experiment, the battery key is pressed before the galvanometer key.

Statement 2 : In post-office box experiment, if galvanometer key is pressed first and then we press battery key, then galvanometer may get damage.

EASY

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

In a meter bridge balance point is found at a distance

l_{1}

with resistances R and S as shown in the figure.

Question Image

When an unknown resistance X is connected in parallel with the resistance S, the balance point shifts to a distance

l_{2}

. Find the expression for X in terms of

l_{1}

l_{2}

and S.

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Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

Shown in the figure below is a meter-bridge set up with null deflection in the galvanometer.

Question Image

The value of the unknown resistor

R

is -

HARD

Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

For a post office box, the graph of galvanometer deflection versus $R$ for the ratio $100 : 1$ is given as shown. A careless student pulls out two non-consecutive values of $R$ as shown in the diagram. Find the value of unknown resistance.
Question Image

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Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

What is the principle of post office box experiment?

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Physics>Electricity and Magnetism>Current Electricity>Meter Bridge

In a meter Bridge experiment resistance

x

is connected in the right gap. When

R_{1}

and

R_{2}

are connected in the left gap separately the balance points are

40 c m

and

50 c m

respectively from the left end. Now if both

R_{1} & R_{2}

are connected in series in the left gap with

x

in the right gap then the new balance point from the left end will be

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Important Questions on Current Electricity

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