Fill in the blanks:
$(a)$. Longer line in the symbol for a cell represents its______terminal.
$(b)$. The combination of two or more cells is called a_________ .
$(c)$. When current is switched ‘on’ in a room heater, it________ .
$(d)$. The safety device based on the heating effect of electric current is called a_________.

AcademicPhysicsNCERTClass 7

$(a)$. Longer line in the symbol for a cell represents its $\underline{positive}$ terminal.

Explanation:

There are two terminals$(positive\ and\ negative)$ in an electric cell. A cell is represented as shown in the figure below. The longer line in the symbol represents the positive terminal of the battery.




$(b)$. The combination of two or more cells is called a $\underline{battery}$.

Explanation:

When two or more electric cells are connected together, this combination is called a battery of cells.


$(c)$. When current is switched ‘on’ in a room heater, it $\underline{produce\ heat}$.

Explanation:

A room heater is a device that converts electrical energy into heat. When the current is passed through the circuit of a room heater, then it starts producing heat. This is called the heating effect of electric current.


$(d)$. The safety device based on the heating effect of electric current is called a $\underline{fuse}$. 

Explanation:

A fuse wire is made of metals that have a low melting point, due to which whenever a slightly higher electric current flows through it, it breaks the wire and hence damage to electrical appliances is prevented. It is based on the heating effect of electric current.

raja
Updated on 10-Oct-2022 13:26:26

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