Login

Q1. Define unit of resistance.(1)

Q2. A 12 V battery is connected across a 6 resistor. Calculate the current passing through the resistor.(Marks : 1 )

What is the difference between the direction of conventional current and the flow of electrons in a circuit?(Marks : 1 )

The filament of an electric toaster draws a current of 40 A which heats for 30 minutes. Determine the amount of charge that flows through the filament.(Marks : 1 )

Differentiate between a cell and a battery.(Marks : 1 )

State Ohm's law.(Marks : 1 )

State the unit of resistivity.(Marks : 1 )

An electric heater has a coil of resistance 100 . How much current will the electric heater draw from a 210 V line?(Marks : 1 )

Which factor is responsible for conduction?(Marks : 1 )

A voltmeter has a high or low resistance explain why?(Marks : 1 )

Does the value of resistance of a conductor depend upon the potential difference applied across it?(Marks : 1 )

State Ohm's law. Represent graphically, the variation of current Ias a function of potential difference V.(Marks : 2 )

Give one difference between conductors and insulators. Giveone example each.(Marks : 2 )

Find the current supplied by the cell in the circuit shown

Why does the process of rubbing cause electrification through the transfer of only the negative charge?(Marks : 2 )

What is the difference between static and current electricity?(Marks : 2 )

Give two conditions needed for the flow of current.(Marks : 2 )

Which physical quantity is measured by the unit kWh or kilowatt-hour?Define kilowatt-hour. (Marks : 2 )

How does resistance of a conductor depend upon the temperature?(Marks : 2 )

The V - I graph of two conductors is described as: (i) conductor 'A'V - I graph is a straight line, (ii) conductor 'B'V - Igraph is a curve. Answer the following:

(a) which one is agood conductor? (b) which conductor will heat up fast? (c) which conductor can be used in a heater? (d) if the length of both conductors is increased whoseresistance will increase in both conductors?(Marks : 2 )

Find the combined resistance in the circuit

Find the Resultant resistance in the given circuit between A and B

Three resistors 2 , 2 and 3 are to be arranged in a combination. (a) Propose a combination of the resistors such that equivalent resistance comesoutto be 1.71 . (b) In which type of combination will the (i) potential difference across each component resistor remain same? (ii) current through each component resistor remain same?(Marks : 2 )

State alternating current. What is meant by AC of frequency 50 Hz? (Marks : 2 )

Ohm's law states that , where V = potential difference applied and I = current produced. (a) Show the above law graphically by plotting V along x-axis and I along y-axis. (b) What physical quantity related to the conductor can you determine from the graph? (c) Define the unit of the physical quantity identified in part (b)

OR

(a) Identify the quantity X that establishes a relation between the resistance and the geometrical factors of a wire. (b) Define the unit of the quantity X (c) Name the class of solids, which have (i) low value of X

(b) high value of X.(Marks : 3 )

In the circuit given below, determine the equivalent resistance between the terminals AB

OR

In the circuit given below, the voltmeter reads 15 V across 5 resistor. Calculate the potential difference across the battery.

Given are the tabulated values of current produced in a circuit for various potential differences applied.

V(volt)

I (ampere)

3

0.7

3.5

0.8

4

0.9

4.5

1

5

1.1

5.5

1.2

(a) Plot the graph using scale and pencil

(b) From the graph, calculate the resistance of the conductor from the graph.

OR

(a) Two cells each of 2V and internal resistance 1.5 are connected in series. This arrangement is used to send the current through a 4 resistor. Find the current? (b) Two wires of same material and same lengths have radii r1 and r2. Compare their resistances.(Marks : 3 )

(a) In which of the following two cases can a '5 ampere fuse' be employed? (i) An electric kettle of 1200 W operating at 220 V. (ii) An electric iron of 900 W operating at 200 V.

(b) Why is earthing essential? Explain with reference to an electrical appliance. (Marks : 3 )

The values of currentIflowing in a given resistor for the corresponding values of potential difference V across the resistor are given as

V(Volt)

0.25

0.5

0.75

1

1.25

1.5

1.75

I(Ampere)

0.25

1

1.75

2.5

3.25

4

4.75

Plot the corresponding V - Igraph. Calculate the resistance of the resistor from the graph.(Marks : 3 )

The values of current I flowing through a given resistor for the various values of potential difference applied are given as below:

V (volt)

I(A)

1 2 3 4 5 6 7

0.5 1 1.5 2 2.5 3 3.5

Plot the graph between V and I. Determine resistance of the conductor from the graph (Marks : 3 )

In the adjacent diagram, find the reading of the ammeter and the voltmeter when (i) key K is open (ii) key K is closed

In the circuit diagram given below

Given that R1 = 4 ; R2 = 6 , R3 = 10 and V = 1.5 volt. Determine: (i) current through each resistor (ii) equivalent resistance of the combination (iii) the total current through the circuit.(Marks : 5 )

Due to time constraints we will not be able to do solve all the questions. Here are the answers to a select few...

.

(1) The unit of resistance is ohm. 1 ohm is defined as the amount of resistance encountered by 1amp of current moving under potential difference of 1 volt.

.

(2) From Ohm's Law

V = IR

or current

I = V/R = 12V / 6ohms = 2 amps

.

(3) Flow of electrons is always opposite to the direction of flow of conventional current.

.

(4) we know that, I = q/t

or amount of charge

q = I.t = 40A x (30x60s)

so, q = 72000 C

.

(5) A cell is a fundamental or basic device which converts chemical energy to electrical energy, it is a single unit. A battery on the other hand is composed of a number of cells.

.

(6) Ohm’s law states that the current (I) flowing through a conductor is directly proportional to the potential difference (V) across the ends of a conductor, provided physical conditions of the conductor such as temperature, mechanical strain etc. are kept constant.

V ∝ I

On removing the proportionality signs we get:

V = IR

Where R is the resistance and is measured in SI unit called ohm(?).

  • 4
View Full Answer

 Q1. Define unit of resistance.(1)

Q2. A 12 V battery is connected across a 6 resistor. Calculate the current passing through the resistor.(Marks : 1 )

What is the difference between the direction of conventional current and the flow of electrons in a circuit?(Marks : 1 )

The filament of an electric toaster draws a current of 40 A which heats for 30 minutes. Determine the amount of charge that flows through the filament.(Marks : 1 )

Differentiate between a cell and a battery.(Marks : 1 )

State Ohm 's law.(Marks : 1 )

State the unit of resistivity.(Marks : 1 )

 

An electric heater has a coil of resistance 100 . How much current will the electric heater draw from a 210 V line?(Marks : 1 )

Which factor is responsible for conduction?(Marks : 1 )

A voltmeter has a high or low resistance explain why?(Marks : 1 )

Does the value of resistance of a conductor depend upon the potential difference applied across it?(Marks : 1 )

State Ohm 's law. Represent graphically, the variation of current Ias a function of potential difference V.(Marks : 2 )

Give one difference between conductors and insulators. Giveone example each.(Marks : 2 )

Find the current supplied by the cell in the circuit shown

Why does the process of rubbing cause electrification through the transfer of only the negative charge?(Marks : 2 )

What is the difference between static and current electricity?(Marks : 2 )

Give two conditions needed for the flow of current.(Marks : 2 )

Which physical quantity is measured by the unit kWh or kilowatt-hour?Define kilowatt-hour. (Marks : 2 )

How does resistance of a conductor depend upon the temperature?(Marks : 2 )

The V - I graph of two conductors is described as:
(i) conductor 'A 'V - I graph is a straight line,
(ii) conductor 'B 'V - Igraph is a curve.

Answer the following:

(a) which one is agood conductor?
(b) which conductor will heat up fast?
(c) which conductor can be used in a heater?
(d) if the length of both conductors is increased whoseresistance will increase in both
conductors?(Marks : 2 )

Find the combined resistance in the circuit

Find the Resultant resistance in the given circuit between A and B

Three resistors 2 , 2 and 3 are to be arranged in a combination.
(a) Propose a combination of the resistors such that equivalent resistance comesoutto be 1.71 .
(b) In which type of combination will the 
(i) potential difference across each component resistor remain same? 
(ii) current through each component resistor remain same?(Marks : 2 )

State alternating current. What is meant by AC of frequency 50 Hz? (Marks : 2 )

Ohm 's law states that , where V = potential difference applied and I = current produced.
(a) Show the above law graphically by plotting V along x-axis and I along y-axis.
(b) What physical quantity related to the conductor can you determine from the graph?
(c) Define the unit of the physical quantity identified in part (b)

 

OR

(a) Identify the quantity X that establishes a relation between the resistance and the geometrical factors of a wire. 
(b) Define the unit of the quantity X 
(c) Name the class of solids, which have 
(i) low value of X

(b) high value of X.(Marks : 3 )

 

In the circuit given below, determine the equivalent resistance between the terminals AB

OR

In the circuit given below, the voltmeter reads 15 V across 5 resistor. Calculate the potential difference across the battery.

 

Given are the tabulated values of current produced in a circuit for various potential differences applied.

 

V(volt)

I (ampere)

3

0.7

3.5

0.8

4

0.9

4.5

1

5

1.1

5.5

1.2

 

(a) Plot the graph using scale and pencil

(b) From the graph, calculate the resistance of the conductor from the graph.

OR

(a) Two cells each of 2V and internal resistance 1.5 are connected in series. This
arrangement is used to send the current through a 4 resistor. Find the current?
(b) Two wires of same material and same lengths have radii r1 and r2. Compare their resistances.(Marks : 3 )

 

(a) In which of the following two cases can a '5 ampere fuse ' be employed?
(i) An electric kettle of 1200 W operating at 220 V.
(ii) An electric iron of 900 W operating at 200 V.

 

(b) Why is earthing essential? Explain with reference to an electrical appliance. (Marks : 3 )

 

The values of currentIflowing in a given resistor for the corresponding values of potential difference V across the resistor are given as

V(Volt)

0.25

0.5

0.75

1

1.25

1.5

1.75

I(Ampere)

0.25

1

1.75

2.5

3.25

4

4.75

 

Plot the corresponding V - Igraph. Calculate the resistance of the resistor from the graph.(Marks : 3 )

 

The values of current I flowing through a given resistor for the various values of potential difference applied are given as below:

V (volt)

I(A)

1
2
3
4
5
6
7

0.5
1
1.5
2
2.5
3
3.5

 

Plot the graph between V and I. Determine resistance of the conductor from the graph (Marks : 3 )

 

In the adjacent diagram, find the reading of the ammeter and the voltmeter when
(i) key K is open
(ii) key K is closed

In the circuit diagram given below

Given that R1 = 4 ; R2 = 6 , R3 = 10 and V = 1.5 volt. 
Determine: 
(i) current through each resistor 
(ii) equivalent resistance of the combination 
(iii) the total current through the circuit.(Marks : 5 )

Asked by Arohit35...(student), +1 more 4 minutes ago
  • -1

1. Resistivity is denoted by the symbol 'ρ' (rho).

=Ohm-m

Hence SI unit is 'ohm meter' or 'Ωm'

2.

A cell is only a single cell but a battery is a group of 2 or more cells

or,

cell is the unit which has two terminals one positive and one negative ...a battery is a group of cells in which one negative terminal is attached to one positive terminal.

or,

Cell:- Cell is the smallest unit of a battery.

Battery:-

A battery is combination of cells. This is why, the DC power supply used in tractors, trucks, inverters etc are called battery (one such battery contain about 4-6 cells).Hence battery provides more voltage.

Ohm’s Law: The ratio of potential difference between the ends of a conductor to the current flowing through the conductor is a constant. This constant is defined as Resistance of the conductor.
Mathematically,

 

 

A voltmeter is basically a galvanometer in a series combination with a very high resistance. So, a voltmeter would have a very high internal resistance. This is because in order to measure the potential difference accurately it has to prevent the flow of current through it as much as possible. A very high resistance solves that purpose.

As a result of this, voltmeters are connected in parallel in an electrical circuit.

For an Ammeter it is entirely opposite, it has a very low resistance to ease the flow of current through it.

Resistance is a material property and does not depend upon current or potential difference. It only depends upon the type of material, its shape and size.

An insulator is a material that does not conduct electricity at all, for example wood. A conductor, conducts electricity, but not that effectively, in other words have high resistance. For example, commonly available can conduct electricity (because of dissolved minerals), but not like copper and iron.

The charges that are at rest are known as static charges and the charges that are in motion gives rise to an effect known as electric current.For example when you comb your hair or when you rub a ball point with your hair you will observe that these bodies will attract some other bodies.These effects are due to the excess or deficiencies of charges in bodies and you are observing the properties of charges which are at rest,i.E attraction or repulsion only. But if you observe a live wire in which we say current will flow if connected to neutral wire then at that time the charges are flowing through the wire due to the presence of potential difference or in simple words due to the application of energy stored in power station.

 

a. Metals are good conductors of heat and electricity.

 

  • 4
What are you looking for?