Question

find out the equivalent resistance of the circuit given along side (8-33h)class 10th​

Answer 1

Answer:

Mathematically, resistivity of the conducting material is given by

p = R x A/J

If l = 1 m, A = 1 m2, then p = R

Hence, the resistivity of the material is defined as the resistance offered by a metallic wire having a unit length and a unit area of cross-section. Since unit length and unit area of cross-section forms a cube, the specific resistance or resistivity can also be defined as the resistance offered by a cube of a material of side 1 m when current flows perpendicularly through the opposite faces. In SI system, its units is

electricity-chapter-wise-important-questions-class-10-science-8

Experiment:

Aim : To study the factors on which resistance of conducting wires depends. Apparatus Required : A cell, an ammeter, nichrome wires of different length but same area of cross-section (thickness), nichrome wires of same length but different thickness, copper and iron wire of the same length and same thickness as that of any nichrome wire.

Procedure :

Connect the cell, an ammeter and plug key in series with nichrome wire of length T (marked 1) in the gap XY as shown.

electricity-chapter-wise-important-questions-class-10-science-9

Close the key and note the reading of ammeter. It measures the current ‘I’1 through the nichrome wire (marked ‘1’).

Replace the marked 1 wire with another nichrome wire having same area of cross-section (thickness) but of double length’2l’ (marked 2).

Note the ammeter reading (I2) again after closing the key.

Again replace the marked 2 wire with marked 3 wire which has the same length but is thicker than marked 1 and 2 nichrome wires. Again note down the current (I3) through this wire.

Unplug the key. Remove marked 3 nichrome wire from the gap XY. Connect the copper wire marked 4 having same length and same area of cross-section as that of nichrome wire marked 1. .

Plug the key again and note the ammeter reading. It measures the current (I4) through copper wire.

Repeat the experiment with iron wire and measure the current (I5).