1. Electricity is a form of --------
a) Force b) energy c) tension d) shock
2. Potential difference is also called --------
a) Volts b) voltage c) coulomb d) Ampere
3. Resistance of a wire is r ohms. The wire is taken is double its length, then its initial resistance in ohms will be ------
a) r/2 b) 4r c) 2r d) r/4
Fill in the blanks with suitable word .
1. Electrical is a Latin word which means ----- ( Charges )
2. The smallest &lightest particle of an atom is the -------(Electron )
3. The SI unit of electromotive force is --------(Volt )
Match the followings
1.charge Ohms ( 4)
2.potential difference Newtons
3.Electric current Volts(2 )
4.Resistance Coulombs (1 )
Answer the following questions :
1. Write the differences between static electricity & electric current.
Static electricity is formed in insulator and it is not movable but electric current is formed in conductors & it is movable.
2. Define electric current?
Flow of electric charges is called electric current.
3. Name the unit of electric charge.
4. Name the unit of electric current.
5. Define potential difference.
The energy required to transport a unit positive charge from one point to another point is called potential difference between those points.
6. Name the unit of potential difference.
7. Define E.M.F (electromotive force)
The potential difference that makes electrons to move in a certain direction within a conductor is called electromotive force.
8. What is resistance?
Opposition offered by the conductor to the flow of charges is called resistance.
9. What is the unit of resistance?
10. On which factors Electric resistance depends?
a) Nature of the material
a) Length of the conductor
c) Thickness of the conductor
d) Temperature of the conductor
11. State Ohm’s law.
At constant temperature the current flowing through a conductor is proportional to the potential difference across the conductor- This is called ohm’s law.
12. Write the formula for Ohm’s law.
13. What are the effects of electric current?
a) Heating effect
b) Magnetic effect
c) Chemical effect
14. What is heating effect of electric current?
When electric current flow through a conductor, it produces heat. This is called Heating effect of electric current.
eg:electric iron box, electric water heater
15. What is magnetic effect of electric current?
When electric current flow through a conductor, it produces magnetic field around it. This is called magnetic effect of electric current.
16. What is chemical effect of electric current?
When electric current flow through an electrolyte, it produces chemical changes this is called chemical effect of electric current.
17. What is electric power?
The rate of work done by electric current is called electric power. Unit of electric power is Watt.
18. Write the precautions to be taken while working with electricity.
a) Unplug all the electrical appliance when not in use or while cleaning.
b) electrical chords must be in good condition
c) Extension cords should not be in continuous use.
d) unwind the cord before using.
e) connect plugs completely.
e) never carry an appliance along with its cord.
f) use electrical appliance with dry hands & wear slippers on dry ground.
g) do not try repair electrical appliance by your own.