electricity

Question 1

electric current

Answer 1

the rate of flow of charge in circuit is called electric current.

Question 2

what can electric charges flow on

Answer 2

The electric charges can flow in conducting mediums from a higher potential to a lower potential.

Question 3

What is ammeter?

Answer 3

Ammeter is a device used to measure electric current.
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Question 4

SI unit of electric current

Answer 4

Ampere (A)

Question 5

what is 1 ampere

Answer 5

1 ampere current is that amount in which 1 coulomb charge flows per second

Question 6

Electromotive force (emf)

Answer 6

emf is the amount of energy converted from non-electrical energy to electrical energy by the source of electric current.

Question 7

SI unit of emf

Answer 7

Its SI unit is volt (V)

Question 8

define 1 volt

Answer 8

If an electric source supplies I J energy to produce 1 C charge, the emf of the source is called 1 volt

Question 9

what is the potential difference or voltage?

Answer 9

The amount of energy converted from electrical to non-electrical energy is called potential difference or voltage.

Question 10

SI unit of voltage.

Answer 10

Volt

Question 11

What is 1J pd.

Answer 11

1j pd is that in which 1-joule work is done by the flow of 1-coulomb charge

Question 12

difference between PD and EMF

Answer 12

emf
-It is the amount of energy converted by non-electrical energy to electrical energy.
-It occurs inside the electric source.
-Its value is greater than the pd of the same circuit.
-it occurs in open circuit.

pd
-It is the amount of non-electrical energy converted from electrical energy.
-It occurs outside the electric source.
-Its value is always less than the emf of the same circuit.
-It occurs in closed circuit.

Question 13

Define electric resistance.

Answer 13

A resistance of a conductor is that property which restricts the movement of free electrons through it.
Its si unit is ohms

Question 14

Define free electron

Answer 14

Free electrons are the electrons which are free to move from one atom to another atom.

Question 15

How do electrons pass?

Answer 15

Most of the metals have free electrons in them. Some of them can vary. But insulators do not have free electron so electric current do not pass through them.

Question 16

Some examples of resistors.

Answer 16

Manganin which is made of copper(83%),
manganese (13%) and nickel(4%).
Nichrome which is made of nickel(60%) and chromium (40%).
Resistors are used in heating substances or tools to produce heat and some metals are also used to produce light ex tungsten .

Question 17

Does the semi-conductor conduct electrons?

Answer 17

Yes, semiconductors conduct electrons but in small amounts. They contain few electrons but they can conduct more electrons in high temperatures.

Question 18

formula to calculate the resistance of a circuit when Current and voltage is given

Answer 18

Resistance = Voltage / current

Question 19

resistance relation with length of wire, diameter of the wire, temperature and nature of the conductor

Answer 19

1. Resistance is directly proportional with the length of the wire.
2. Resistance is directly proportional to the temperature.
3. Resistance is inversely proportional to the thickness of the conductor.
4. Resistance depends on which material the conductor is made of.

Question 20

Who developed Ohm’s law?

Answer 20

German physicist, George Simon Ohm in1826 AD.

Question 21

What does Ohm’s law states?

Answer 21

Ohm’s law states that electric current is directly proportional to the potential difference across its two ends at a constant physical condition.

Question 22

What are the different types of combinations of resistors (load) in a circuit?

Answer 22

1. Parallel combination.
2. Series combination.

Question 23

Briefly describe the series combination.

Answer 23

It is the type of combination in which the resistors are joined in such a way that there is a single path for each resistor.
We cannot run electric appliances of different power in this combination and also we cannot use a separate switch for each resistors or load.
In this combination current flowing through the resistor are constant but the potential difference is different.

Question 24

Point out the disadvantages of series combination.

Answer 24

1. In this combination if one load fail to work then the entire circuit will not work.
2. At same voltage electric appliances with different power cannot run.

Question 25

Briefly describe about parallel combination.

Answer 25

Parallel combination is the type of combination in which each resistor is joined in such a way that there is a separate path for each of them.
The current passing through the different load are different but the voltage is the same throughout the circuit.

Question 26

What is equivalence resistance?

Answer 26

Equivalence resistance is the sum of all the individual resistances in the circuit.

Question 27

Use of heating effect of electric current.

Answer 27

1. It is used in our home for different purposes.

Question 28

Use of heating effect of electric current

Answer 28

1.It is used in our homes for different purposes.
2. It is also used to dry things.
3. I is used in filament lamps.
4. it is used in protection of the electric circuit by means of fuses