Dr SM Saliem

WELCOME TO THIS

VIDEO LECTURE

Dr SM Saliem

Associate Professor

University Women’s Polytechnic AMU, Aligarh

I SEM DIP ENGG, 2020-2021 APPLIED PHYSICS LAB-I

(WPH-191)

EXPERIMENT 2: (SCREW GAUGE)

OBJECT:

To determine mass per unit length of a given wire using screw gauge.

APPARATUS:

Screw Gauge and uniform cylindrical wire (iron metal).

FORMULA:

m= mass per unit length d=diameter of wire

ρ=density of material of wire

4

2



 d

m 

DIAGRAM OF SCREW GAUGE:

PICTURE OF SCREW GAUGE

PITCH:

Pitch p is the ratio of distance x moved by the screw and y no of rotations given to circular scale.

mm mm y

p x 0 . 5 10

5 





LEAST COUNT:

Least count is the ratio of pitch and total number of divisions on the

circular scale.

mm mm N

C p

L 0 . 01

50 5 . . 0

.   

ZERO ERROR: FIRST READING

ZERO ERROR: SECOND READING

ZERO ERROR: THIRD READING

ZERO ERROR:

e₁= - (50-46) x 0.01 mm= - 0.04 mm e₂= - (50-45) x 0.01 mm= - 0.05 mm e₃= - (50-47) x 0.01 mm= - 0.03 mm

Mean zero error e = - 0.04 mm Zero correction -e = 0.04 mm

OBSERVATION: DIAMETER READING #1

OBSERVATION: DIAMETER READING #2

OBSERVATION: DIAMETER READING #3

OBSERVATION: DIAMETER READING #4

OBSERVATION: DIAMETER READING #5

OBSERVATION TABLE:

S.NO MSR

m (mm) CSR

n OBSERVED DIA.

d₀=m+nxL.C. (mm) 1.

2.

3.

4.

5.

2.0 2.0 2.0 2.0 2.0

20 21 22 20 22

2.0+20x0.01=2.20 2.0+21x0.01=2.21 2.0+22x0.01=2.22 2.0+20x0.01=2.20 2.0+22x0.01=2.22

CALCULATION:

Mean observed diameter d0=2.21mm

Corrected diameter (d)

=observed diameter+zero correction =2.21+0.04=2.25 mm

d=2.25 x10^-3 m

Density of iron metal (ρ)

ρ=7.85x10³kg/m³

MASS PER UNIT LENGTH:

 

m kg

m m m m d

/ 10

2 . 31

4

10 786

. 124

4

10 85

. 7 10

25 .

2 14

. 3

4

3

3

2 3 3 2











 







 

  

RESULT:

Mass per unit length of the given

uniform cylindrical wire (iron metal) using Screw Gauge is found to be

31.2x10^-3 kg/m or 31.2 g/m

THANKS