Physics, asked by bikashjha5608, 20 hours ago

determine the resistivity of 2/3 wire by plotting graph for potential difference vs current . full experiment​

Answers

Answered by bhuvna789456
59

"GIVEN":

To determine the resistivity of 2/3 wire by plotting graph for potential difference vs current

Apparatus Required:

  • A wire of unknown resistance
  • battery
  • voltmeter
  • milliammeter
  • rheostat
  • plug key
  • connecting wires
  • piece of sandpaper

Theory:

  • According to ohm's law, the electric current flowing through a conductor is directly proportional to the potential difference across its end.

  • The physical state(pressure, temperature ,and dimensions) of the conductor remains unchanged.

  • If I is the current flowing through the conductor and V is the potential difference across its end, then.

  • I∝V

  • V∝I

                  ₍or₎                 - ohms law

  • V=RI

  • V/I = constant(R)

  • R∝L/A⇒ R=ρ L/A

  • ρ= RA/L

  • When R is the constant of electrical resistance of the conductor. Resistance R depends of the dimensions and material of the conductor.

  • The resistance of a material and its length and area of the cross-section is given by the formula

  • R=ρ I/A

  • Where ρ is the specific resistance or resistivity .

Procedure:

  • Take the sand paper clean the ends of connecting wire.

  • Connect the resistance , rheostat , battery, voltmeter , and ammeter.

  • The voltmeter and milliammeter coincide with the zero mark on measuring scale in pointer . If not, adjust the pointer to zero mark base using a screwdriver.

  • Note the range and the least count of the voltmeter and milliammeter. Insert the key(k) slide the rheostat end the current flow is minimum.

  • Note the voltmeter and milliammeter readings. Remove the key k and wire cool. Insert the key and increase the voltage by moving rheostat . Note the milliammeter and voltmeter reading.

Observation:

  •  Range of Voltmeter=0-2v
  •  Range of Ammeter=0-2A
  •  Least count of Voltmeter=0.05V
  •  Least count of Ammeter=0.05A
  •  Length of each wire=100 cm
  •  Zero error=Nill

OBSERVATION TABLE:

Wire 1:

--------------------------------------------------------------------------------------------------------------

s.no      Ammeter reading (I)A          Voltmeter reading (v) v         R=V/I ohm

--------------------------------------------------------------------------------------------------------------

1                       0.1                                         0.25                                     2.5

2                      0.2                                        0.50                                     2.5

3                      0.3                                         1.00                                     2.5

-------------------------------------------------------------------------------------------------------------

                                                                                                      Mean=2.5ohm

Wire 2:

--------------------------------------------------------------------------------------------------------------

s.no          Ammeter reading(I)A           Voltmeter reading(v) v       R=V/I ohm

-------------------------------------------------------------------------------------------------------------

1                        0.05                                   0.25                                  5

2                       0.10                                    0.50                                  5

3                       0.15                                    0.75                                   5  

------------------------------------------------------------------------------------------------------------

                                                                                                     Mean=5 ohm

Observation table for diameter by using screw guage :

  • Pitch=1mm
  • No .of divisions on circular scale=100
  • Least count =1/100 =0.01mm=0,001 cm

--------------------------------------------------------------------------------------------------------------

s.no       Main scale reading             No .of circular          n*L.C      Diameter

                  (N mm)                      divisions coincide(n)                    N + n(L.C)

--------------------------------------------------------------------------------------------------------------

Wire 1            0                                       50                     50*0.001      0+0.05

                                                                                               cm       D1=0.05cm

--------------------------------------------------------------------------------------------------------------

Wire 2           0                                        44                   44*0,001       0+0.044

                                                                                           cm       D2=0.044cm

--------------------------------------------------------------------------------------------------------------

Calculation:

  • From graph .resistance

          wire 1=2.5 ohm

           wire 2=5 ohm

           Length of each wire=100cm

  • Diameter D1=0.05 cm, D2=0.044cm
  • Resistivity:- ρ1=R₁πD₁²/4L  

               = 2.5*3.14*0.05*0.05/4*100

               = 4.9*10⁻⁵ohm cm

  • Resistivity :-ρ2=R₂πD₂²/4L

                =5*3.14*0.044*0.044/4*100

                = 7.5*10⁻⁵ohm cm

Attachments:
Answered by moraiyasam
3

Answer:

uppar hai

Explanation:

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