ENGINEERING SCIENCE LAB - I&II PHYSICS (2007) - Madin ...

LAB MANUAL

ENGINEERING SCIENCE LAB - I&II

PHYSICS (2007)

ENGINEERING SCIENCE LAB - I&II ( PHYSICS) REVISION-2015

MA’DIN POLYTECHNIC COLLEGE, MLAPPURAM 1

SYLLABUS

On completion of the course the student will be able to:

1. To measure volume of a cylinder using vernier calipers.

2. To measure volume of a wire using screw gauge.

3. To determine focal length of a convex lens by displacement method.

4. To determine the velocity of sound in air at room temperature using resonance column.

5. To determine spring constant using Hooke’s law..

6. To determine acceleration due to gravity using simple pendulum.

7. To verify law of resistances.

8. To determine specific resistance of material using Meter Bridge.

9. To determine Internal Resistance of a Primary Cell using Potentiometer.

10. To plot characteristics of photoelectric cell (photoelectric current vs. intensity of light

and voltage applied)

11. To determine the mass of the given body using moment bar.

12. To determine the mass of a body by parallelogram method and by Lami’s theorem.

13. To verify Ohm’s law and to determine the resistance of the given wire.

14.To determine the coefficient of viscosity of a highly viscous liquid.

15.To determine the relative density using U-tube apparutus

MA'DIN POLYTECHNIC COLLEGE

ENGINEERING PHYSICS LAB

MA’DIN POLYTECHNIC COLLEGE, MALAPPURAM 2

OBSERVATION:

Value of 1 main scale division = ……….mm No. of divisions on vernier = …………. Least count = value of 1 main scale division / No. of divisions on the vernier = ………….. mm =…….….cm Zero correction = ………… To find height h

Trail

No: MSR(cm) VSR MSR + (VSR×LC)

CORRECTED

READING

1

2

3

4

5

Mean height h = …………cm

To find external diameter D

Trail

No: MSR(cm) VSR MSR + (VSR×LC)

CORRECTED

READING

1

2

3

Mean diameter D = …………cm

External radius R = ………….cm

To find internal diameter d

Trail

No: MSR(mm) VSR MSR + (VSR×LC)

CORRECTED

READING

1

2

3

Mean diameter d = ………..cm

Mean radius r = ………………..cm

Volume of the hollow cylinder v = πh (R2-r

2) = ……………………….cm

3

=……………………… m3




Expt. No: 01

Date:

VERNIER CALIPERS

AIM:

To determine the volume of the given hollow cylinder.

APPARATUS:

Vernier calipers, hollow cylinder.

PRINCIPLE:

Least Count = Value of 1 main scale division / No. of divisions on vernier.

Total reading = MSR+(VSR × LC)……

Volume of hollow cylinder = πh (R2- r

2)

PROCEDURE:

The least count of the apparatus is determined first. The apparatus is then checked to find the zero

correction, if any. To check this, the two jaws are kept in contact. If the zero of the main scale coincides

with the zero of the vernier, there is no zero error. If the zero of the vernier is on to the right of main scale

zero, it is a case of positive zero error and the zero correction is negative, if zero of vernier is on to the left

of main scale zero, zero error is negative and zero correction is positive. Now the cylinder is gently gripped

in between the jaws to find the length. The reading of the main scale just before the zero of the vernier is

noted as the MSR (Main Scale Reading). The vernier scale division coinciding with any division on the

main scale is noted as the VSR (Vernier Scale Reading). Now the total reading is calculated using the

formula (MSR+ VSR×LC).The procedure is repeated at least 4 times and the mean value is calculated as h.

Similarly, the external diameter and the internal diameter of the cylinder are determined. The external

radius R and internal radius r are then calculated. The volume is determined using the formula π h (R2- r

2).

RESULT:

Volume of the given cylinder = ………………m3




OBSERVATION:

Distance moved for 4 rotations = ………………………..mm

Pitch = Distance moved for 1 rotation = ……………………..mm

No. of divisions on the head scale =

Least count = pitch / no. of divisions on head scale = ………………..mm

Zero correction = ………..head scale divisions

Trail

No: PSR OBSERVED HSR

CORRECTED

HSR

PSR+(Corrected

HSR× LC)

1

2

3

4

5

Mean diameter , d = …………….mm

Radius of the wire, r=d/2 = …………….mm= ---------- X10-3

m

Length of the wire, l= --------cm=--------X10-2

m

Volume of the wire, V= πr2l = …………….m

3




Expt. No: 02

Date:

SCREW GAUGE

AIM:

To determine the volume of the given wire.

APPARATUS:

Screw gauge, wire, meter scale..

PRINCIPLE:

Pitch p is the distance advanced by the screw during one rotation. Least count is the distance

advanced by the screw as it is rotated through one division.

Least count = pitch / No. of divisions on Head scale.

Total reading = PSR + Correct HSR × LC

Volume of the wire = πr2l

PROCEDURE:

The apparatus is first of all checked to find the zero correction if any. For this, the screw is

tightened without keeping any object in between the screw tip and stud. If the zero of the Head scale

coincides with the reference line, there is no zero error. No correction is needed in such case. But if the zero

of the head scale is above the index line, zero correction is positive. If the zero of the head scale is below

the reference line the zero correction is negative.

The pitch of the screw is then found out. For this, the screw is rotated 4 times and the distance

moved by the screw due to one rotation (pitch) is calculated. Now, the number of divisions on the head

scale is noted and the least count is calculated. The wire is gently gripped in between the screw tip and the

stud. The last fully visible reading on the pitch scale is noted as the Pitch Scale Reading (PSR).The reading

of the head scale against the reference line is noted as the observed HSR. The zero correction is accounted

with this observed HSR and the correct HSR is calculated. Now the total reading is calculated using the

formula PSR + (correct HSR × LC). The experiment is repeated by keeping the wire at different positions

and the mean thickness is determined.The length of the wire , l is measured by using a meter scale.

The volume of the wire is calculated by using the formula, V= πr2l

RESULT:

Volume of the wire = …………………m3




OBSERVATION:

Trail

No:

LENGTH (l)

in m

TIME MEAN t

PERIOD

T=t/20 T

2 l / T

2

1 2

Mean l / T2 = …………………

g = 4π2× l / T

2 = ……………………. m/s2




Expt. No: 03

Date:

SIMPLE PENDULUM AIMS:

1. To determine the value of acceleration due to gravity (g).

2. To determine the length of the seconds pendulum.

APPARATUS:

Simple pendulum, stop watch.

PRINCIPLE:

Acceleration due to gravity g = 4π2× l/T

2

A seconds pendulum is a simple pendulum having period of 2 seconds.

PROCEDURE:

The pendulum is set for a length 0.6m. (Length if the pendulum is the distance between the point of

suspension and the centre of gravity of the bob). The time for 20 oscillations is noted and the period is

calculated. This is repeated and the mean value of period is taken. The experiment is repeated for lengths

0.7m, 0.8m, 0.9m and 1m and in each case the value of l/T2 is used to determine g.

A graph is plotted with length along the X-axis and T2 along the Y-axis. A straight line graph is

drawn including maximum number of points. From the graph determine the value of length corresponding

to T2 equal to 4.

RESULTS:

1. Acceleration due to gravity g = …………………….. m/s2

2. Length of seconds pendulum = …………………… m.




OBSERVATION:

No:

Mass

suspended

in Kg

(M)

Pointer reading Extension in

m

(l)

Load=Mg

K=Mg/l

Loading Unloading Mean

Mean k = ----------N/m.




Expt. No:04

Date:

HOOKE’S LAW (HELICAL SPRING I)

AIM:

To determine the spring constant using Hooke’s law.

APPARATUS:

Hooke’s law apparatus, standard masses

PRINCIPLE:

According to Hooke’s law, the extension produced on a body is directly proportional to the load

applied. If l is the extension produced by a spring due to a load Mg, then spring constant, k=load/extension.

k= Mg/l.

PROCEDURE:

The spring is brought to the elastic mood by loading and unloading it a number of times. Now the

spring is loaded in steps of 50gm and in each case the reading of the pointer is taken. The readings are taken

in steps of 50gm during unloading also. Now the extension for each load is calculated.Then spring constant

can be determined using the formula,

k= Mg/l.

RESULT:

Spring constant of the spring= …………….N/m.




OBSERVATIONS:-

No:

Mass

suspended

in Kg

(M)

Time for 20 oscillations

T=t/20

T2

M/T2

1 2 Mean t

Mean M/T2=…………

Spring constant K=4π2× M/T

2

=………………..N/m




Expt. No:05

Date:

HELICAL SPRING II AIMS:

To determine the spring constant by oscillation method.

APPARATUS:

Helical spring,load,stop watch.

PRINCIPLE:

Spring constant K = 4π2× M/T

2

PROCEDURE:

The mass is suspended on the spring and time for 20 oscillation is measured.The mass is increased

by 50g and repeated the experiment for fve times.The mean M/T2 is measured.Then the spring

constant is given by

K = 4π2× M/T

2

RESULT:

Spring constant of the spring= …………….N/m.




OBSERVATION:

No: V (Volt) I (Ampere) R = 𝑽

𝑰 Ω




Expt. No: 06

Date:

OHM’S LAW

AIM:

To verify Ohm’s law and to determine the resistance of a conductor.

APPARATUS:

Battery, voltmeter, Ammeter, Rheostat, Key, Resistor

PRINCIPLE:

At constant temperature, the current through a conductor is directly proportional to the potential

difference. V

I = R where R is the resistance of the conductor.

PROCEDURE:

Connections are made as shown in the figure. The rheostat is adjusted to read a potential of 1V.The

corresponding ammeter reading is noted. The voltmeter and ammeter readings are taken by increasing the

voltages in steps of 0.5V. In each case, the value of V/I is calculated. Its mean value gives the resistance of

the conductor.

RESULT:

Resistance of the conductor = …………..Ω.




OBSERVATION :

Standard mass W = …………… g

Trail No: BG(cm) AG(cm) M = (𝑾 × 𝑨𝑮)/ 𝑩𝑮

Mean m = …………

= …………… × 10-3

kg




Expt. No: 07

Date:

MOMENT BAR

AIM :

To determine the mass of the given body

APPARATUS:

Moment bar, slotted weights

PRINCIPLE:

For a rigid body supported at its centre of gravity, the anticlockwise moment produced by

the weight of the given body is equal to the clockwise moment produced by the slotted weight.

Here,

W × AG = M × BG

Or

M = (W × AG )

BG

PROCEDURE:

The meter scale is suspended at its centre of gravity G. The given body is suspended on one

side at a convenient point B, say at a distance 5cm. Now a standard mass m is suspended on the

other side of the string. The position (A) of the standard mass is so adjusted that the scale is in

equilibrium keeping the horizontal position. The distance BG is measured and the value of W is

calculated. The experiment is repeated for different values of AG and in each case the value of BG

is determined. RESULT:

Mass of the given body = ………….kg




OBSERVATION:

SL

No: P Q OA OB OC OC × SCALE MEAN




Expt. No: 08

Date:

CONCURRENT FORCES AIM:

To determine the mass of a given body applying parallelogram law and by Lami’s theorem.

APPARATUS:

Parallelogram law apparatus, slotted weights

PRINCIPLE:

If two forces acting at a point are represented in magnitude and direction by the adjacent sides of a

parallelogram drawn from the point, the diagonal drawn from the point represents the resultant in

magnitude and direction. The length of diagonal multiplied by the scale factor gives the mass of the body.

According to Lami’s theorem ,

P/sin α = Q/ sin β = W/sin γ.

i.e. . W = P sin γ/sin α = Q sin γ / sin β.

W

PROCEDURE:

Slotted masses, 100g each are suspended from both sides (P&Q) and the body whose mass is to be

determined is suspended from the middle (W). A convenient scale is chosen (e.g.: 50gm = 1 cm). The

parallelogram is drawn with OA representing the force P and OB representing the force Q. The length of the

diagonal OC is measured. OC multiplied with the scale factor (OC × 50gm in this case) gives the mass of

the given body. The experiment is repeated with a different set of weights as P and Q and the mass is again

determined.

The angles α , β and γ opposite to the forces P, Q and W are measured. Then the mass of the body

calculated by the formula

W = P sin γ/sin α = Q sin γ / sin β.

RESULT:

Mass of the given body = …………..kg




OBSERVATION:

Distant object method:-

Displacement method:-

SL

No:

Distance between

screen and

object(D)

Displacement of

lens(d)

f = (D2 – d

2)/4D.

Mean f

Distance between the lens and image of distant

object.

1

2

3

Mean (f)




Expt. No: 09

Date:

CONVEX LENS

AIM:

To determine the focal length of the given convex lens by displacement method.

APPARATUS:

Convex lens, illuminated wire gauze, screen

PRINCIPLE:

The two points of the principal axis of a convex lens at which the positions of the object and image are

interchangeable are called conjugate points. If D is the distance of an object and its real image and d is the

displacement of the convex lens for the conjugate positions, then the focal length

f = (D2 – d

2)/4D.

D

SOURCE L1 L2 IMAGE

d

PROCEDURE:

The positions of the object and the screen are kept fixed and the distance D between them is measured.

The convex lens is placed between the object and the screen. The lens is moved slowly from the object

towards the screen until a position L1 is reached for which a well defined and magnified image is formed on

the screen. The position of L1 is marked.

The lens is then moved further towards the screen until at a position L2 we get a well defined diminished

image on the screen. The position L2 is marked. The distance between L1 and L2 is measured as d.The

experiment is repeated by changing the value of D keeping in mind that D has to be always greater than 4f.

Then the focal length is calculated using the formula,

f = (D2 – d

2)/4D.

RESULT:

The focal length of the given lens = …………………MA'DIN POLYTECHNIC COLLEGE



TABULATIONS

No. Height of water

column h1(cm)

Height of liquid of

column h2(cm)

h1/h2

1

2

3

4

5

Mean value of relative density h1/h2 = -----------------

Density of the liquid = 1000 x (h1/h2) = --------------- kg/m3




Expt no:10

Date:

BALANCING LIQUID COLUMNS

U-TUBE

AIM

To determine the relative density of a liquid does not mix with water

APPARATUS

U-tube, water, scale and the given liquid

PRINCIPLE

Relative density = height of water column

Height of liquid column

= h1/h2

Density of the liquid = (h1/h2) x 1000 kg/m3

PROCEDURE

A long U tube is fixed to a stand with its limbs vertical. Water is poured through

one of the limbs and the given liquid (kerosene) is poured through the other limb.

The quantities of water and liquid added are adjusted such that the water fills the

bend and common surface of contact C is above the bend. In figure .AC represents

the level of common surface. AB and BD represent the heights of water column

and liquid column above the common surface. Height of the water column h1 and

the height of the liquid column h2 above the plane surface of separation are

measured

RESULT

1. Relative density of the liquid = ------------------

2.Density of the liquid = ------------------




TABULATION

No.

Frequency f

(Hz)

l1

(cm)

l2

(cm)

Vt = 2 f (l2-l1)

(m/s)

1

2

3

4

Mean vt = ------------- m/s




Expt no:11

Date:

RESONANCE COLUMN

AIM

To determine the velocity of sound in air

APPATRATUS

Resonance column apparatus, tuning fork and meter scale

PRINCIPLE

If l1 and l2 are the first and second resonance lengths with a tuning fork of

frequency f, the velocity of sound at room temperature is given by the

formula

Vt = 2 f (l2-l1)

PROCEDURE

The resonance tube is initially adjusted so that the length of the air column

above water level is very small. The vibrating tuning fork is held close to the

mouth of the tube and the tube is gradually raised until the sound heard is

maximum. The length of the air column l1 is measured. The tube is further

raised keeping the vibrating tuning fork close to its mouth. When maximum

sound is heard again, the length l2 of the air column is measured. The length

l2 corresponds to the second resonant length as shown in figure. The

experiment is repeated with tuning forks of different frequencies. l1 and l2

are measured in each case. The velocity of sound at room temperature is

calculated using the relation

Vt = 2 f (l2-l1)

RESULT

Velocity of sound at room temperature = --------------m/s




TABULATIONS

Measurement of resistance

No

R

Balancing length lx

Mean

lx

X = 𝑅𝑙𝑥

100−𝑙𝑥

Before

interchange

After

interchange

1

2

3

4

Mean value of X = ---------Ω

Measurement of radius

Zero correction = -------------divisions

Distance for 6 rotations = --------mm

Pitch = -------------mm

Least count = -------------mm

No P.S.R

(mm)

H.S.D Corrected H.S.D Diameter (mm)

1

2

3

4

Mean diameter = -----------mm

Radius = -----------mm = -----------m

Length of the wire L = -----------m

Specific resistance 𝜌 = 𝑋𝜋𝑟2

𝐿 = ------------ Ωm




Expt No:12

Date : METER BRIDGE

AIM

To determine the resistance and specific resistance of a metal wire

APPARATUS

Meter bridge, Leclanche cell, resistance box, resistance wire and table

galvanometer.

PRINCIPLE

The meter bridge is based on the principle of Wheastone’s network

PROCEDURE

The connections are made as shown in figure. A resistance of 1ohm is

introduced in the resistance box R. The jockey is moved along the wire AB

and the balancing length lx is determined here lx is the length AJ adjacent to

the unknown resistance X. When balance is obtained, the galvanometer

shows no deflection. Resistance in the box is changed to 2 ohm, 3ohm, and 4

ohm. The balance length lx is obtained in each case. The unknown resistance

X and the resistance box R are the interchanged. The balancing length lx is

measured in each case with resistance 1ohm, 2ohm, 3ohm, and 4ohm in the

resistance box. It is to be remembered that the length lx in this case is

measured from B to J because the resistances are interchanged in the gaps.

The mean value of lx is calculated for each case for each value of R.

The resistance X is calculated using the relation

X = 𝑅𝑙𝑥

100−𝑙𝑥

The diameter of the resistance wire X is accurately measured using a screw

gauge. The radius r of the wire is thus determined. The length of the wire L

is measured using meter scale.

The specific resistance 𝜌 = 𝑋𝜋𝑟2

𝐿

RESULT

Resistance of the wire = ----------Ω

Specific resistance 𝜌 = ----------Ωm





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