Class 10 Science Chapter 12 Important Questions 2021-2022
| Class: 10 | Science |
| Chapter: 12 | Important Questions with Answers |
Class 10 Science Chapter 12 Important Questions For Exams
Class 10 Science Chapter 12 Important Questions, short and long answers type extra questions with answers. These questions are useful for boards who are using NCERT Books for Class 10 Science for session 2021-2022. NCERT Solutions and Important Questions collectively provide a goodd practice for exams.
Important Question
SET - 01
1. How Is Electricity Much More Useful Than Other Forms Of Energy?
Ans - As compared to other forms of energy electricity has the following important advantages:
(i) Electricity is the most convenient sources of energy.
(ii) It can readily have transmitted over large distances with relatively small loss in energy.
(iii) It can be easily converted into other forms of energy like heat, light, sound, motion, etc.
2. How Is Static Electricity Being Different From Current Electricity?
Ans :- Electricity has two main branches:
(i) Static electricity: It deals with the physical phenomena produced by the electric charge at rest.
(ii) Current electricity: It deals with the physical phenomena produced by electric charge in motion.
3. What Is Constitutes An Electric Circuit?
Ans :- The flow of electric charges across a cross-section of a conductor constitutes an electric current. For example, a stream of electrons moving through a conducting wire constitutes an electric current.
4.What Is An Electric Circuit? Distinguish Between An Open And A Closed Circuit?
Ans :-A closed and continuous path along which an electric current flows is called an electric circuit.
In a torch a switch provides a conducting a link between a battery and a bulb. When the switch is turned ON an electric current flows through the bulb and it gives light. Such a continuous and closed path of an electric current is called an electric circuit. When the circuit is broken anywhere (or the switch is turned OFF), the current stops flowing and the bulb does not glow.
An electric circuit through which no current flows is called an open circuit.
An electric circuit through which current flows continuously is called a closed circuit.
5.What Is An Electrochemical Cell Or Voltaic Cell Or Galvanic Cell? Give Its Circuit Symbol.
Ans :- A device which converts chemical energy into electric energy is called an electrochemical cell or voltaic cell or galvanic cell. It is a source used for producing a steady current
SET – 02
1.Distinguish Between Conventional Current And Electronic Current.
Ans :- Conventional current and electronic current: When a conductor AB is connected across the terminals of a cell, free electrons begin to drift or move from its end B (connected to the negative terminals of the cell) to the end A (connected to the positive terminal of the cell). The current constituted by flowing electrons is called electronic current. Clearly, the direction of electronic current is from negative terminal to positive terminal.
By convection the direction of motion of positive charges is taken as the direction of electric current. It is from positive terminal to negative terminal. As the electrons are negatively charged, the direction of conventional current in an electric circuit is taken as opposite to the direction of the flow of electrons.
2.What Is An Ammeter? How Is It Connected In A Circuit?
Ans :- Ammeter: An ammeter (ampere + meter) is a device used to measure electric current in a circuit.
An ammeter is always is always connected in series in a circuit so that entire current, which we wish to measure flows through it.
3.How Is Electric Potential Analogous To Temperature?
Ans :- Just as heat flows from higher temperature to lower temperature, positive charges flow from higher potential to lower potential.
4.What Is SI Unit Of Electric Potential?
Ans:- It is volt and has the symbol V.
5.State Ohm’s Law And Write The Condition In Which This Law Is Obeyed?
Ans :- Ohm’s law: This law states that the current (I) flowing through a conductor is directly proportional to the potential difference (V) applied across its ends, provided the temperature and other physical conditions remain unchanged.
Mathematically,
The proportional constant R is called the resistance of the conductor.
Set – 3
1.
Name And Define The SI Unit Of Resistance?
Ans :- SI unit of
resistance is ohm: The resistance of a conductor is said to be 1 ohm if a
current of 1 ampere flows through it an applying a potential difference of 1
volt across its ends.
1 Ohm = (1 Volt )/(1 ampere )
2. What Is The Cause Of
Resistance Of A Conductor?
Ans :- When free electrons drift inside a conductor
they get frequent collisions. This is the basic cause of resistance.
3. What Is The Function Of
Rheostat In An Electric Circuit?
Ans - It changes the current in a circuit due to the
change in its resistance.
4.List The Factors On Which The Resistance Of A Conductor
Depends. Write The Formula Showing Relation Of Resistance With These Factor.
Ans :- Factors affecting the resistance: At a
constant temperature the resistance of a conductor depends on the following
factors:
(i) Length: Resistance R of a conductor is
directly proportional to its length L, i.e., R ∝ L
(ii) Area of cross-section: Resistance R of
conductor is inversely proportional to its area of cross-section i.e., R ∝ 1/A
(iii) Nature of the material: Resistance also
depends on the nature of the material of which the conductor is made. The
resistance of a copper wire is much less than that of a nichrome wire of same
length and area of cross-section.
Combining the above factors, we get, R∝ L/A
The proportionality constant is called resistivity
or specific resistance which depends on the nature of the material.
