(a) What is an electrical fuse? State two characteristics of an electrical fuse.
(b) What is internal resistance of a cell? Write two factors on which it depends.
(c) In the circuit diagram given below, a cell of 9 V and internal resistance 0.5 Ω is connected across a resistor A of 2 Ω in series and two resistors 2 Ω and 6 Ω which are in parallel.


Find:
(i) the total resistance
(ii) the total current
(iii) the current in the 6 Ω resistor
(iv) the potential difference across the terminals of the cell.

Dear student,

a   fuse is a short piece of wire made up of a material of high resistivity and of low melting point, So that it may easily melt due to overheating due to the excessive flow of electric current. The thickness of the fuse wire is different in different fuses depending on the amount of current which is permitted to flow through them.

The material used for fuse elements must be of low melting point, low ohmic loss, high conductivity (or low resistivity), low cost and free from detraction. The material used for making fuse element has a low melting point such as tin, lead, or zinc.


The resistance within a battery, or other voltage source, that causes a drop in the source voltage when there is a current is called internal resistance of the cell. 
Larger the separation between the electrodes of the cell, more the length of the electrolyte through which current has to flow and consequently a higher value of internal resistance

ii)Greater the conductivity of the electrolyte, lesser is the internal resistance of the cell. i.e. internal resistance depends on the nature of the electrolyte.

Post other question in a separate thread

Regards

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