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# Class 10 FRANK Solutions Physics Chapter 4.1 - Ohm's Law and Electrical Circuits

Learn better with our Frank Solutions for ICSE Class 10 Physics Chapter 4.1 Ohm’s Law and Electrical Circuits. Revise the differences between a battery and a cell. Use our solutions to understand how to correctly draw a circuit diagram. Our expert solutions will also help you to solve Physics numerical problems such as calculating the potential difference or finding the value of the resistance of a resistor.

TopperLearning’s study materials are designed according to the latest ICSE Class 10 Physics syllabus. You can explore our complete learning resources such as practice tests, sample papers and video lessons to revise and improve your exam score.

## Ohm's Law and Electrical Circuits Exercise 173

### Solution 1

An electric cell is a device in which a constant difference in potential is maintained between the two conductors by a chemical reaction. Thus, a cell can be used as a source of electrons or current. In a cell, chemical energy changes into electrical energy when it is in use.

### Solution 2 ### Solution 3

An electrical circuit is a continuous path comprising of conducting wires and resistances between the terminals of a battery, along which an electric current is set up. It is represented by drawing a circuit diagram.

### Solution 4 ### Solution 5

A diagram indicating how various components in an electrical circuit have been connected using symbols for those components is a circuit diagram.

### Solution 6

In the given diagram, ammeter is connected in parallel and voltmeter in series, which is wrong. Also the terminals of the two devices are wrongly connected to the battery.
Correct diagram: ### Solution 7

According to Ohm's law, the current flowing in a conductor is directly proportional to the potential difference across its ends provided the physical conditions and temperature of conductor remains constant.
No, it is not always true. E.g. Diode valve, junction diode etc. do not obey Ohm's law.

### Solution 8

The obstruction offered to the flow of current by the wire is called its electrical resistance. It is a kind of friction between the free electrons and the atoms of the conductor along which they flow.
Its SI unit is 'ohm'.

### Solution 9

The physical quantity is 'resistance'.

### Solution 10

Resistance of a conductor is said to be 1 ohm, if 1 ampere current flows through it, when the potential difference across its ends is 1 volt.

### Solution 11

No, Ohm's law does not hold good for semiconductors and electrolytic solutions.

### Solution 12

Factors on which the resistance of a conductor depends are:
(i) Nature of conductor: different materials have different concentration of free electrons and therefore resistance of a conductor depends on its material.
(ii) Length of conductor: Resistance of a conductor is directly proportional to the length of a conductor.
(iii) Area of cross-section of a conductor: Resistance of a conductor is inversely proportional to the area of cross-section of the uniform wire.
(iv) Temperature of conductor: In general for metallic conductors, higher the temperature larger is the resistance.

### Solution 13

An equivalent resistor is that resistor which when replace any combination of resistors the current through the circuit is not altered or changed.

### Solution 14 ### Solution 15

The slope of the graph (dV/dI) gives the value of resistance.

### Solution 16

The resistivity of a material is the resistance of a wire of that material of unit length and unit area of cross-section.

### Solution 17 ### Solution 18

Conductance of a conductor is the reciprocal of resistance of that conductor. Its unit is mho.

### Solution 19

(i) Metals e.g. copper
(ii) Alloys e.g. Constantan
(iii) Semiconductors e.g. Germanium

### Solution 20 ## Ohm's Law and Electrical Circuits Exercise 174

### Solution 21

Ohm's law relates the current in a conductor to the potential difference across its ends.
According to Ohm's law, the current flowing in a conductor is directly proportional to the potential difference across its ends provided the physical conditions and temperature of conductor remains constant.

### Solution 22

If the conductor is made thinner, electrons get smaller area of cross-section to flow and it therefore, offers a large resistance.

### Solution 23

At constant temperature, if current is plotted against potential difference, the plot will be a straight line making some slope with the x-axis as shown in figure below: ### Solution 24

The instrument used to measure electric current is called an ammeter. It has a low resistance and is always connected in series.

### Solution 25

The instrument used to measure electric potential or potential difference is called a voltmeter. It has a very high resistance and is always connected in parallel.

### Solution 26

An ammeter has a low resistance.

### Solution 27

A voltmeter has a high resistance.

### Solution 28

A key acts as a switch in an electric circuit. It helps to open or close the circuit as required.

### Solution 29

A rheostat is a device used in electric circuit to regulate current without changing the voltage source. It is also called variable resistance.

### Solution 30 ### Solution 31 ### Solution 32 ### Solution 33 ### Solution 34 ### Solution 35 ### Solution 36 ### Solution 37 ### Solution 38 ### Solution 39 ### Solution 40

Two uses of conductors:
(i) Connecting wires are made of conductors like copper.
(ii) Conductors are used as electrolytes in cells

## Ohm's Law and Electrical Circuits Exercise 175

(a) Ampere
(b) Volt
(c) Coulomb

### Solution 42

The potential difference between two points may be defined as the work done in moving a unit positive charge from one point to the other.

### Solution 43

Electrical potential is a 'scalar' quantity.

### Solution 44

Electric intensity is defined as the force experienced by a unit positive charge when kept at that point.
Its SI unit is newton per coulomb. It is a vector quantity.

### Solution 45

Joule/coulomb is known as 'volt'.

### Solution 46

Work done = charge x potential difference
Or, W = 5 x 1 = 5 J

### Solution 47

(ii) potential difference

(iv) voltmeter

### Solution 49

Charges move in a definite direction in a conductor when a potential difference is applied across the ends of the conductor.

### Solution 50

We can maintain a potential difference between the ends of a conductor by connecting the two ends of the conductor to the two terminals of a battery or cell.

### Solution 51

The rate of movement of charge from one point to another through a section of the conductor is called electric current. Current refers to rate of flow of charges in a conductor.
I = Q/t

### Solution 52

The direction of conventional current is taken as the direction of flow of positive charges.
The direction of electronic current is taken as opposite to the direction of motion of electrons.

### Solution 53

Current defines the rate of flow of charges in a conductor.

### Solution 54

Current is measured by an ammeter.

### Solution 55 ### Solution 56 ### Solution 57 ### Solution 58

To get a total resistance less than 2 ohm, the given resistors should be connected in parallel because in parallel combination the equivalent resistance is less than the resistance smallest connected resistor.

### Solution 59 ### Solution 60 