Class 7 Science Electric Current and its effects

Class 7 Science Electric Current and its effects

 

Class 7 Science Electric Current and its effects Fill in the blanks:

1. The longer line in the symbol for a cell represents its ………..terminal. [positive]
2. The combination of two or more cells is called a ………[battery]
3. When current is switched ‘on’ in a room heater, it ………[still hot and give heat]
4. The safety device based on the heating effect of electric current is called a ………..[fuse]

Mark ‘T’ if the statement is true and ‘F’ if it is false:

1. To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell. (False)
2. When the electric current through the fuse exceeds a certain limit, the fuse wire melts and breaks. (True)
3. An electromagnet does not attract a piece of iron. (False)
4. An electric bell has an electromagnet. (True)

 

Class 7 Science Electric Current and its effects Extra Que Ans

Fill in the blanks:

1. A …………is a visual representation of an electric circuit.[ circuit diagram]
2. ……………is a group of cells connected in a series.[ Battery]
3. ………..is the flow of electricity in the bulb, the wires, the switch, and the battery.[ Electric current]
4. The ……….terminal of a cell is represented by a longer line in its symbol.[ positive]
5. ………….terminals are represented by short, thick lines in cell symbols.[ Negative]
6. An …………..is a magnet made using electric current.[ electromagnet]
7. Electric currents flow through wires and produce…………[ magnetic fields]

 

Answer the following questions in short:

 

Que:- Give examples of devices that uses battery.

Torches, transistors, toys, TV remote controls, and many other devices use batteries.

 

Que:- What device is used to make or break an electric circuit?

Switch

 

Que:- In an electric circuit diagram, which part is represented by straight lines?

Connecting wires

 

Que:- Which metal is used to make the filament of a bulb?

Tungsten

 

Que:- Which device is used in place of fuse?

MCB

 

Que:- Define battery.

Battery is a collection of two or more cells with positive and negative terminals connected to each other.

 

Que:- If the filament of the bulb is broken, would the circuit be complete? Would the bulb still glow?

Electric current passes through a thin wire inside the bulb, called the filament. When the filament is broken, the bulb becomes fuse.

 

Que:- Define electromagnets.

When the electric current is switched off, the coil generally loses its magnetism Such coils are called electromagnets.

 

Que:- Define circuit.

The path along which an electric current flows between the two terminals of a cell or battery is known as a circuit.

Que:- Define circuit diagram.

The circuit diagram shows how various components in a circuit have been connected by using the electrical symbols for the components.

 

Que:- Which 3 effects can produce by electric current?

An electric current can produce 3 effects:-