Free Printable Current Electricity XII

1.

A Carbon Resistor is marked in colour bands of Red, Black,Orange,Silver.What is the resistance and tolerance value of the resistor ?

a)

20 kilo ohm & +- 10%

b)

18 kilo ohm & +-5%

c)

25 kilo ohm & +- 10%

d)

20 kilo ohm

2.

A cell of emf (E) and internal resistance (r) draws a current (I). Write a relation between terminal voltage (V) in terms of E,I,r. ?

(a)

3.

As the temperature of a conductor increases both it's Resistivity and Conductivity change.Will the ratio of its Resistivity and conductivity

a)

Increases

b)

Decreases

c)

Remain same

d)

None of these

4.

When is the Wheatstone bridge is most sensitive ?

a)

When all the four resistances of the bridge are equal

b)

When the bridge is balanced

c)

When high amount of current is flowing through the bridge

d)

When a very low amount of current is flowing through the bridge

5.

The unit of electric power is

a)

Volt

b)

Joule

c)

kWh

d)

Watt

6.

What will be the new resistivity of a metallic wire if it's length becomes double

a)

Increases two times

b)

Becomes half

c)

Increases four times

d)

Remains same

7.

Wheatstone is one type of ______ bridge

a)

AC

b)

DC

c)

DAC

d)

ADC

8.

Equation for this circuit is :

a)

R1R3 = R2Rx

b)

R1R2 = R3Rx

c)

R1Rx = R3R2

d)

R1Rg = RxRg

9.

Calculate R if P=1 kΩ, Q=2.5 kΩ and S=4kΩ

a)

1.6 Ω

b)

0.16 kΩ

c)

16 kΩ

d)

1.6 kΩ

10.

Kirchhoff's junction rule is a reflection of

a)

Conservation of current density vector

b)

Conservation of charge and no accumulation of charge at the the junction

c)

the momentum with which a charged particle approaches a junction is unchanged as the charged particle leaves the junction

d)

Conservation of energy

11.

Which of the following characteristics of electrons determines the current in a conductor?

a)

Drift velocity alone

b)

Thermal velocity alone

c)

Both A and B

d)

Neither A nor B

12.

13. Drift velocity vd varies with the intensity of electric field as per the relation

a)

(a) v_d ∝ E

b)

(b) v_d ∝ 1/E

c)

(c) v_d = constant

d)

(d) v_d ∝ E²

13.

14. For measurement of potential difference, a potentiometer is preferred over voltmeter because

a)

(a) potentiometer is more sensitive than voltmeter.

b)

(b) the resistance of potentiometer is less than voltmeter.

c)

(c) potentiometer is cheaper than voltmeter.

d)

(d) potentiometer does not take current from the circuit.

14.

15. From the graph between current I and voltage V shown below, identify the portion corresponding to negative resistance

a)

(a) AB

b)

(b) BC

c)

(c) CD

d)

(d) DE

15.

16. Which of the following I-V graph represents ohmic conductors?

a)

(a) A

b)

(b) B

c)

(c) C

d)

(d) D

16.

20. The resistivity of alloy manganin is

a)

(a) Nearly independent of temperature

b)

(b) Increases rapidly with increase in temperature

c)

(c) Decreases with increase in temperature

d)

(d) Increases rapidly with decrease in temperature

17.

18. In a Wheatstone bridge if the battery and galvanometer are interchanged then the deflection in galvanometer will

a)

(a) change in previous direction

b)

(b) not change

c)

(c) change in opposite direction

d)

(d) none of these.

18.

20. The figure below shows currents in a part of electric circuit. The current i is ________ .

a)

(a) 2 A

b)

(b) 1.3 A

c)

(c) 1.7 A

d)

(d) 1 A

19.

A closed path that electric current follows

a)

Voltage

b)

Current

c)

Resistance

d)

Circuit

20.

In the equation I = nAvq, what does v represent?

a)

The speed of the electrons

b)

The average speed of the electrons

c)

The velocity of the electrons

d)

The average velocity of the electrons

e)

the fastest speed of all electrons

21.

In the equation I=nAvq, which option(s) describe the meaning of n?

a)

the charge carrier density

b)

the number of charge carriers per unit volume

c)

the number of charge carriers per m³

d)

the number of charge carriers in the wires

e)

the total charge carriers available in the battery

22.

If the current in a specific copper wire increases this can be due to _____________________.

a)

An increase in the charge carrier density

b)

An increase in the electron drift speed

c)

An increase in its cross sectional area

d)

An increase in the charge of electrons

23.

If the current at a given point in a circuit is 2.5 Amp, then how many electrons pass that point on the circuit in a time period of 1 minute.

Answer:

a)

9.375 x 10²⁰ electrons

b)

9.375 x 10²¹ electrons

c)

9.375 x 10¹⁹ electrons

d)

9.375 x 10¹⁸ electrons

24.

An ideal voltmeter in physics has...

a)

...an easily readable scale

b)

...an infinite resistance

c)

...zero resistance

d)

...a negligible internal resistance

25.

In Physics, an ideal ammeter has...

a)

...a 10A fuse

b)

...infinite resistance

c)

...an autoranging function

d)

...zero resistance

26.

A car battery has an emf of 12V and an internal resistance of 0.005Ω. The terminal voltage when a load current of 100A is drawn is...

a)

11.5V

b)

0.5V

c)

7.0V

d)

11.5A

27.

The cell has internal resistance, r, and electromotive force of 1.5 V.
What is the reading of voltmeter when the switch is closed?

a)

More than 3.0 V

b)

Less than 1.5 V

c)

More than 1.5 V

d)

1.5 V

28.

A battery has an e.m.f of 6.0 V. When it is connected to an external resistor, the potential different is 2.6 V and the current is 0.6 A.
What is the value of the internal resistance?

a)

3.4 Ω

b)

4.3 Ω

c)

4.4 Ω

d)

5.7 Ω

29.

What is the internal resistance of the battery in the circuit?

a)

9.40 Ω

b)

11.50 Ω

c)

12.50 Ω

d)

13.50 Ω

30.

What is emf?

a)

the electro motive "force" or the force on electrons

b)

the electromotive "force" or the Voltage of a cell measured when there is no current flowing

c)

the electromotive "field" or the Voltage of a cell measured when there is no current

d)

the electromotive "force" or Voltage of a cell measured when connected to a circuit

31.

One dry cell with e.m.f value of 2V and internal resistance 1Ω is connected to one resistor 4Ω

a)

0.4A

b)

0.5A

c)

2.0A

d)

2.5A

32.

A battery of e.m.f. 12.0 V, with an internal resistance of 3.0 Ω, is connected in series with a 15.0 Ω resistor and a battery of e.m.f. 9.0 V, which has an internal resistance of 2.0 Ω. Calculate the p.d. of the 15Ω resistor.

a)

15.75V

b)

5.25V

c)

15.25V

d)

15.50V

33.

What is internal resistance?

a)

the resistance inside the cell that increases with more current drawn from the cell

b)

the resistance inside the cell that decreases with more current drawn from the cell

c)

the resistance inside the cell that remains constant as the current drawn from the cell changes

d)

the resistance inside each component which increases as more resistances are added in series

34.

A potentiometer wire of length 1 m is connected to a driver cell of emf 3 V as shown in the figure. When a cell of 1×5 V emf is used in the secondary circuit, the balance point is found to be 60 cm. On replacing this cell and using a cell of unknown emf, the balance point shifts to 80 cm.Calculate unknown emf of the cell.

a)

1 V

b)

1.5 V

c)

3 V

d)

2 V

e)

2.2 V

35.

The following graph shows the variation of terminal potential difference V, across a combination of three cells in series to a resistor, versus the current. Calculate the emf and internal resistance of each cell

a)

E = 6 V & r = 3 ohm

b)

E = 2 V & r = 1 ohm

c)

E = 6 V & r = 1 ohm

d)

E = 2 V & r = 3 ohm

e)

E = 1 V & r = 1 ohm

36.

Which copper wire has the lowest resistance?

a)

1 metre of 1 mm diameter wire

b)

0.5 metre of 1 mm diameter wire

c)

0.5 metre of 0.5 mm diameter wire

d)

1 metere of 0.5 mm diameter wire

37.

The length of a certain conductor of resistance 100 is doubled and its cross-sectional area is halved. Its new resistance is

a)

100

b)

50

c)

200

d)

400

38.

Factor which does not affect the resistance

a)

Type of material

b)

Length of material

c)

Mass of the material

d)

Area of the material

39.

A 1.5 m length of wire has a cross-sectional area 5.0 × 10^–8 m². When the potential difference across its ends is 0.20 V, it carries a current of 0.40 A. The resistivity of the material from which the wire is made is

a)

6.0 × 10⁷ Ω m

b)

1.7 × 10^–8 Ω m

c)

1.1 × 10⁶ Ω m

d)

9.4 × 10^–7 Ω m

40.

For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material?

a)

power

b)

resistivity

c)

resistance

d)

1/(resistance)

41.

For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material?

a)

power

b)

resistivity

c)

resistance

d)

1/(resistance)

42.

Potential difference across it's terminals when cell is in open

circuit

a)

emf

b)

Terminal potential difference

c)

lost volt

d)

work

43.

If the Galvanometer needle keeps shaking in an experiment what you conclude?

a)

connections may be loose

b)

emf of the cell may be varying

c)

faulty potentiometer

d)

galvanometer may be faulty

44.

What happens to the balancing length if the value of the variable resistance R is increased?

a)

decreases

b)

increases

c)

no change

d)

can not predict

45.

A 47K ohm resistor would have which colors on its first three bands?

a)

Yellow, Violet, White

b)

Yellow, Violet, Orange

c)

Red, White, Blue

d)

Orange, Yellow, Violet

46.

The gold color band refers to__________tolerance.

a)

+ / - 20%

b)

+ / - 10%

c)

+ / - 5%

d)

zero

47.

What is the maximum value in the tolerance range of a resistor with color code Red-Violet-Orange-Gold?

a)

29.7 K Ω

b)

32.4 K Ω

c)

28.35 K Ω

d)

27 kΩ

48.

What is the multiplier for color Green?

a)

x10,000

b)

x1,000,000

c)

x100,000

d)

x1,000

49.

The conductance of a conductor of resistance 2 milli ohm

a)

5 Siemen

b)

0.5 Siemen

c)

50 Siemen

d)

500 Siemen

50.

72 cells of internal resistance 5 Ohm and emf 2.0 volt are used to send current through an external circuit of resistance 10 Ohm. What is the maximum current in the circuit

a)

6/35 amp

b)

12/35 Amp

c)

24/35 Amp

d)

35/24 Amp

51.

The average relaxation time during collision of electrons with atoms is

a)

10^-14sec

b)

10^-10

c)

10⁴

d)

10¹⁴

52.

The dimensional formula of current density is

a)

⌈ L^-2 A ⌉

b)

⌈ L²A^-1⌉

c)

⌊ L^-1 A² ⌋

53.

n e V_{d = ____ ?}

a)

σ

b)

ρ

c)

j

d)

G

54.

Current density formula is

a)

Electric Current / length

b)

Electric Current / area

c)

Electric Current / volume

d)

None of above

55.

Directions of drift velocity of electrons and electric field are

a)

In same direction

b)

Opposite to each other

c)

Fluctuated

d)

None of above

56.

A conductor of cross-sectional area 0.10 $mm^2$ carries a current of 2.5 A. If the number of conduction electrons per cubic metre is $1.0\times10^{28\ }$ $m^{-3}$ . What is the value of drift velocity of the free electrons in the conductor?

a)

1.6 $\times10^{-2}\ m\ s^{-1}$

b)

3.9 $\times10^{-2}\ m\ s^{-1}$

c)

3.0 $\times10^{-3\ }m\ s^{-1}$

d)

6.2 $\times10^{-3\ }m\ s^{-1}$

57.

A conductor of length 2.0 m and cross-sectional area 5.0 $\times10^{-6}\ m^2$ carries a current of 6.0 A. If the drift velocity of the conduction electrons is 1.5 $\times10^{-4}\ m\ s^{-1}$ , what is the number of electrons in the conductor?

a)

2.5 $\times10^{23}$

b)

2.9 $\times10^{23}$

c)

4.2 $\times10^{23}$

d)

5.0 $\times10^{23}$

58.

A tungsten wire of length 1.00 m and cross-sectional area 2.01 $\times10^{-6}\ m^2$ carries a current of 5.00 A. If the number of free electrons per unit volume is 4.3 $\times10^{28}$ , what is the time taken by an electron to travel from one end of the wire to the other end?

a)

1.81 $\times10^3$ s

b)

2.77 $\times10^3$ s

c)

4.51 $\times10^3$ s

d)

7.25 $\times10^3$ s

59.

There are 6.23 $\times10^{24}$ free electrons per $cm^3$ in a wire. The average drift velocity of the electrons is 1.1 $\times10^{-3}m\ s^{-1}$ . Calculate the current density in the wire.

a)

1.0 $\times10^3A\ m^{-2}$

b)

6.9 $\times10^6A\ m^{-2}$

c)

2.1 $\times10^9A\ m^{-2}$

d)

1.1 $\times10^9A\ m^{-2}$

60.

A current flows in a copper wire. The current density in the wire is 1.4 $\times10^6A\ m^{-2}$ . If the number of free electrons in 1 $m^3$ of wire is 8.4 $\times10^{28}$ , what is the drift velocity of the electrons?

a)

1.04 $\times10^{-4}m\ s^{-1}$

b)

3.10 $\times10^{-4}m\ s^{-1}$

c)

1.67 $\times10^{-3}m\ s^{-1}$

d)

1.90 $\times10^{-3}m\ s^{-1}$

61.

A charge of 60 Coulomb flows in a wire for 45 minutes. If the diameter of the wire is 1.0 mm, what is the current density in the wire?

a)

2.2 $\times10^4A\ m^{-2}$

b)

2.8 $\times10^4A\ m^{-2}$

c)

7.6 $\times10^7A\ m^{-2}$

d)

5.6 $\times10^8A\ m^{-2}$

62.

The conductivity of copper is 6.0 $\times10^7\Omega^{-1}m^{-1}.$ The free electron density copper is 8.45 $\times10^{28}m^{-3}$ . Estimate the mean time between collisions of free electrons and positive ions in copper.

a)

2.52 $\times10^{-14}\ s$

b)

4.04 $\times10^{-33}\ s$

c)

4.04 $\times10^{-14}\ s$

d)

7.10 $\times10^{-22}\ s$

Current Electricity XII

Total questions: 62

Worksheet time: 16hrs 30mins

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