Free Printable Current electricity

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Current electricity

Total questions: 30

Worksheet time: 24mins

Name

Class

Date

The potential difference between points A and B of adjoining figure

$\frac{2}{3}$ V

$\frac{8}{9}V$

$\frac{4}{3}V$

$2\ V$

Drift velocity $v_d$ varies with the intensity of electric field as per the relation

$v_d\ \alpha\ E$

$v_d\ \alpha\ \frac{1}{E}$

v = Constant

$v_d\ \alpha\ \ E^2$

The colour sequence in a carbon resistor is red, brown, orange and silver. The resistance of the resistor is

21 $\times$ 10³ $\pm$ 10%

23 $\times$ 10¹ $\pm$ 10

21 $\times$ 10³ $\pm$ 5%

12 $\times$ 10³ $\pm$ 5%

In the network of resistors shown in the adjoining figure, the equivalent resistance between A and B is

54 $\Omega$

18 $\Omega$

36 $\Omega$

9 $\Omega$

In the given circuit the current I₁is

0.4 A

0.8 A

- 0.4 A

-0.8 A

In the given current distribution what is the value of I

3 A

5 A

8 A

2 A

Two cells when connected in series are balanced on 8m on a potentiometer. If the cells are connected with polarities of one of the cell is reversed, they balance on 2m. The ratio of e.m.f.'s of the two cells is

3:5

5:3

4:3

3:4

A cell of internal resistance 3 ohm and emf 10 volt is connected to a uniform wire of length 500 cm and resistance 3 ohm. The potential gradient in the wire is

30 mV/cm

10 mV/cm

20 mV/cm

4 mV/cm

The potential difference (V_A-V_B) between the points A and B in the figure below Is:

6 V

9 V

3 V

-3 V

10.

A potentiometer wire of length L and a resistance r are connected in series with a battery of e.m.f. E₁ and resistance r₁. An unknown e.m.f. E is balanced at a length l of the potentiometer wire.

The e.m.f. E will be given by:

$\frac{LE_1r}{\left(r+r_1\right)l}$

$\frac{L\ E_1r}{l\ r_2}$

$\frac{E_1r}{\left(r+r_1\right)}\ \frac{l}{L}$

$\frac{E_1l}{L}$

11.

The current I and voltage V graphs for a given metallic wire at te=wo different tempratures T1 and T2 are shown in gigure .It conclude that

T1 >T2

T1<T2

T1=T2

T1=2 T2

12.

if two identical cells , when connected in series or in parallel,supply same amount of current through an external resistance of 2 ohm .the internal resistance of each cell is

2 ohm

4 ohm

6 ohm

1 ohm

13.

Two resistance filaments of samen length are connected first in series and then in parrallel.Find the power dsipation in both cases assumming equal current flows inmain circuit

1:4

4:1

1:2

2:1

14.

When a current is passed in conductor,3 ⁰C rise in temprature is observed. If the strength ofcurrent is made thrice, then rise in the temprature will approximtley be

36^oC

27^oC

18^oC

9^oC

15.

Two wire of same material but of diffrent diameter carry the same current I.If the ratio of their diameter is 2:1 then corresponding ratio of theirmean drift velocities will be

4:1

1:1

1:2

1:4

16.

The mobility of free electrons in a metal is proportional to

$\frac{e}{m}\tau$

$\frac{e}{m\tau}$

$\frac{m}{e\tau}$

$\frac{m}{e}\tau$

17.

8 identical cells ,each of emf E and internal resistance r ,are connected in series.If polarity of two cell is reversed,the total internal resistance in the circuit wil be

18.

The sensitivity of potentiometer can be increased by

increasing the length of potentiometer wire

decreasing the length og potentiometer wire

increasing the potential gradient( $\frac{V}{l}$ )

increasing the emf of primary cell

19.

When a potential difference V is applied accross conductor at a temprature T,the drift velocity of electron is propotional to

$\sqrt[]{V}$

$\sqrt[]{T}$

20.

In the experiment of potentiometer ,at the balanced point there is no current in

in main circuit

galvanometer circuit

potentiometer circuit

both main and galvanometer circuit

21.

In an experiment of wheatstone bridge ,the position of galvanometer and cell is interchanged,then balanced point will be

will change

remains unchanged

depends upon internal resistance and resistance of galvanometer

None of these

22.

Which of follwing charactristics of electrons determines the current in the conductor

thermal velocity of electrons alone

drift velocity of electrons alone

tboth drift velocity and thermal velocity of electrons alone

niether drift velocity and thermal velocity

23.

A cpacitor is attached with cell of emf E and internal resistance r,the potential difference across capacitor

equal to E

less than E

greater than E

less than and equal to E

24.

In the potentiometer the balanced point obtained when

emf of battery cell becomes equal to experimental cell(primary cell)

potential difference between the +ve end of the battery to jockey becomes equal to experimental cell(primary cell)

potential difference of the wire between the +ve end of the cell to jockey becomes equal to emf of the battery

the potential difference across the potentiometer wire becomes equal to emf of the battery

25.

When a metal conductor connected to left gap of a meter bridge is heated, the balancing point

shifts towards right

shifts towards left

remains unchanged

remains at zero

26.

AB is a wire of potentiometer with the increase in the value of resistance R, the shift in the balance point J will be

towards B

towards A

remains constant

first towards B then back towards A.

27.

The resistivity of alloy manganin is

Nearly independent of temperature

Increases rapidly with increase in temperature

Decreases with increase in temperature

Increases rapidly with decrease in temperature

28.

Emf of a cell is(a)

the maximum potential difference between the terminals of a cell when no current is drawn from the cell.

the force required to push the electrons in the circuit.

the potential difference between the positive and negative terminal of a cell in a closed circuit.

less than terminal potential difference of the cell.

29.

A battery of emf E and internal resistance r is connected across a resistance R. Resistance R can be adjusted to any value greater than or equal to zero. A graph is plotted between the current (i) passing through the resistance and potential difference (V) across it. Select the correct alternative(s).

internal resistance of battery is 5Ω

emf of the battery is 20V

maximum current which can be taken from the battery is 4A

V- I graph can never be a straight line as shown in figure.

30.

A cell supplies a current of 0.9 A through a 2 ohm resistor and a current of 0.3 A through 7 ohm resistor. The internal resistance of the cell is

2.0 ohm

1.5 ohm

1 ohm

0.5 ohm

100 %

Current electricity

Total questions: 30

Worksheet time: 24mins

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