Sonometer relation between frequency and the length, GSEB physics practical std 11 & 12

Sonometer

Sonometer

AIM :-

To study the relation between frequency and the length of a stretched string with the help of a sonometer.

PRECAUTIONS

1  The wire should be of uniform cross-section and there should not be any twist or bend in it.

2   The pulley should rotate without friction.

3   Put that much weight  in the pan so that the deformation produced in the wire should not exceed the elastic limit.

4   The stem of the tuning fork, not its prongs, should be placed on the sonometer box or on the support.

Apparatus:-  A sonometer,  tuning forks ( of frequencies from 256 Hz – 512 Hz),  a pan or a hanger of known weight,  four to five 500 gm weights, a paper rider, a rubber-pad and a meter rule. 

Sonometer Apparatus

Sonometer Practical

OBSERVATION TABLE

Sonometer reading

Sonometer Graph

For more details View Video.

To study the relation between frequency and the length of a stretched string with the help of a sonometer.

RATE OF FLOW OF WATER physics practical GSEB std 11 & 12

RATE OF FLOW OF WATER

RATE OF FLOW OF WATER

AIM :-

Fill water in a cylinder vessel, connected with a capillary, upto some height h_o. Allow water to flow through capillary in a controlled way and measure the height (h) of water, in vessel, at regular intervals (t) of time. Take ten such observations. Draw a graph of h ® t and find the half-life of the flow of water.

Apparatus :

Ø  A burette

Ø   A stand

Ø   A beaker

Ø   A stop-watch

Ø   A capillary of fine bore

Ø   A rubber tube

Ø   A pinch cock

Ø   water

Rate of flow of water apparatus

Rate of flow of water Practical

Calculation

Rate of flow of water observation table

Rate of flow of water graph

Rate of flow of water calculation

Graph of rate of flow of water

For more details view Video.

RATE OF FLOW OF WATER

Ohm's law physics practical for ITI fitter & GSEB Std 8 & 12

Ohm's Law 

Ohm's Law

AIM :-

A voltmeter, a current meter, and an unknown resistance etc. are given to you. Prepare an appropriate circuit to verify Ohm’s law. With  appropriate values of current and voltages, only with the help of calculations, determine  the value of unknown resistance.

PRINCIPLE

Potential difference in a conductor produces electric current.

APPARATUS :-

A unknown resistance,

a voltmeter (0 - 10 V),

a milliammeter (0 - 500mA), a battery,

a rheostat,

a tap key,

connecting wires.

PRECAUTIONS : -

1. All the connections must be tight.
2. Plastic or rubber should not be pressed below the connecting terminals.
3. When current does not flow in a circuit the pointer in both ammeter and voltmeter must be on zero. If it is not so then adjust the pointer on zero or consider the zero error.
4. Range of the meters must be appropriate.
5. Choose a proper scale while plotting the graph so that the graph is sufficiently large and it occupies most part of the graph-paper.

Ohm's Law apparatus

Ohm's law Line diagram

Ohm's law line diagram 

Ohm's law practical

Ohm's law observation table

Ohm's law graph

For more details View Video.

Ohm's Law

Change in Chemical reactions Exothermic OR Endothermic GSEB Science 8 to 12

Exothermic reaction 

To measure the change in chemical reactions and conclude whether the reaction is exothermic or endothermic.

AIM  : To measure the change in chemical reactions and conclude whether the reaction is exothermic or endothermic.

THEORY  :  During the chemical reaction if the temperature increases the reaction is exothermic and if temperature decreases the reaction is endothermic.

APPARATUS  : Conical flask, 250 ml Beaker, Stand, Thermometer,  Glass rod, measuring cylinder, stirrer.

Exothermic Reaction (step 1)

Exothermic Reaction (step 2)

Exothermic Reaction (step 3)

MATERIAL       :  Dilute hydrochloric acid, Zinc metal, Solid ammonium chloride,

Observation

(1) initial temperature of dilute hydrochloric acid              ⁰ C.

(2) Temperature of the mixture when Zinc metal dissolves in    hydrochloric acid =         ⁰ C.

(3) Difference of temperature =                    ⁰ C.

(4) Give chemical reaction of Zinc metal with hydrochloric acid.

NOTE     :  (1)  Similarly heat of neutralization in neutralization reaction between                      dilute hydrochloric acid and sodium hydroxide can be measured.

                   (2)  The increase in temperature can be noted when dissolution of solid                    sodium hydroxide in water is carried out.

PRACTICAL USES

The combustion reactions of kerosene, Petrol, LPG are exothermic, therefore these substance are used as fuel.

Endothermic Reaction :

Endothermic reaction (step 1)

Endothermic reaction (step 2)

Endothermic reaction (step 3)

Observation

(1) Initial temperature of water =         ⁰ C.

(2) Temperature o ammonium chloride solution when dissolved in        water    =              ⁰ C.

(3) Difference between temperatures  =                    ⁰ C.

NOTE  :   *    Similarly when Sodium nitrite is dissolved in water decrease in              temperature occurs.

PRACTICAL USES

Some substances absorb heat from atmosphere, during the reaction therefore used to reduce the temperature.

. TO VERIFY THE LAWS OF REFLECTION USING A PLANE MIRROR GSEB Std 8 to 12 Science practical

Reflection of Plain mirror 

Reflection of Plain mirror.

Aim :   To verify the laws of reflection using a plane mirror.

Principle    :  When a ray of light is incident on a reflecting surface, it changes its direction of motion and travels in the original medium following certain laws. This phenomenon is called  reflection of light.

Apparatus : Drawing board, a drawing paper (White), a plane mirror, a foot-rule, a pencil, four pins, four push pins, a protactor, a stand for the plane mirror.

Apparatus : Drawing board, a drawing paper (White), a plane mirror, a foot-rule, a pencil, four pins, four push pins, a protactor, a stand for the plane mirror.

Reflection of Plain mirror Practical

Reflection of Plain mirror

Reflection of Plain mirror

Reflection of Plain mirror

Reflection of Plain mirror

Ø  First of all fix the white drawing paper on the drawing board using push pins.

Ø  First of all fix the white drawing paper on the drawing board using push pins. Place the plane mirror along with its stand and fix its position AB.

Ø  Now draw a line PQ which passes through the mid-point ‘P’ of AB and perpendicular to AB.

Ø  Now draw a line PQ which passes through the mid-point ‘P’ of AB and perpendicular to AB.

Ø  PQ is called the normal to AB.

Ø  Draw a ray RP which makes some angle with the normal (PQ).

Ø  Draw a ray RP which makes some angle with the normal (PQ). On the ray RP fix two pins P₁ and P₂ vertically with 2-3 cm separation between them. Ray RP is incident ray.

Ø  Now from the other side of PQ , (in which incident ray is not there) see the images of pins P₁ and P₂ fix other two pins P₃ and P₄ vertically so that pins P₃, P₄ and images P₁ and P₂ appears collinear at their lower ends.

Ø  Now remove the pins and the mirror. Join the marks of P₃ andP₄ and obtain the reflected ray PS.

Ø  Repeat  the experiment for different angles of incidence. Measure angle of incidence and angle of reflection. Note your reading in the observations table.

Reflection of Plain mirror

Reflection of Plain mirror Observation table

Conclusion : 

Practical uses :  We can study the laws of reflection. We can also study the images obtained by the plane mirror. We can come to know how reflection is used in various optical appliances, e.g., periscope, keleidoscope.

For more details view Video.

Reflection of Plain mirror.

focal length of a concave mirror by obtaining an image of a far distance object, GBSE for std 8 to 10 science practical

Focal length of a concave mirror

     

Focal length

To determine the focal length of a concave mirror by obtaining an image of a far distance object

AIM :- To determine the focal length of a concave mirror by obtaining an image of a far distance object.

APPARATUS  :- A concave  mirror of diameter approximately 10 cm., stand, screen, foot-rule, etc.

PRINCIPLE   :- Rays coming from a far distance object are almost parallel. Such rays, parallel to the principal axis, after being reflected by a concave mirror, are focused at the principal focus of the mirror. Distance between the principal focus and the pole of the mirror is known as the focal length.

NOTE  :  Here screen should be taken small, so that rays coming from the object are not blocked by the screen itself. Diameter of the screen here can be    approximately 3 – 4 cm.

Focal length of Concave mirror

Focal length of Concave mirror,

Focal length of concave mirror Adjustment

Focal Length of Concave mirror

OBSERVATION

Distance between the pole of the mirror and the image on the 

screen = focal-length =                              CM.

CONCLUSION

PRACTICAL USES

Concave mirrors are used in head lights of vehicles, solar furnace, solar cooker, shaving mrror, etc. For all such applcatons it is necessary to know the focal length of the mirror to used. It can be estimated using the given method.

For more details view Video.

Focal length

Post office box, principle of balanced Wheatstone bridge. physics practical std 11 & 12 GSEB

Post Office box

POST OFFICE BOX

Aim:-

A post office box and other necessary instruments are given to you. Take three appropriate ratios of the resistances in the two arms of Post Office Box and determine the values of two unknown resistances.

Now connect the unknown resistances in series and parallel respectively and verify the laws of series and parallel combinations of resistances.

PRINCIPLE :-

It works on the principle of balanced Wheatstone bridge.

APPARATUS :-

A Battery,

unknown resistance (Rx & Ry),

Post Office Box,

a galvanometer,

rheostat,

connecting wires

Post office box Apparatus

CONDITION  1 :- 

Connect unknown resistance      Rx between C and D

Post office line diagram condition 1

Post office condition 1 Practical

 CONDITION 2 :- 

Connect unknown resistance      Ry between C and D

 

Post office line diagram condition 2

Post office condition 2 practical

CONDITION 3 :- 

Connect unknown resistance      Rx & Ry in SERIES between C and D

Post office series connection 

Post office series connection practical

CONDITION 4 :- 

Connect unknown resistance      Rx & Ry in PARALLEL between C and D

Post office parallel connection condition 4

Post office box parallel connection 

Post office box observation table

Post office box calculations

Precautions

(1)   All plug keys of Post Office Box must be tight.

(2)    Contact points of K₁ and K₂ must be cleaned  with sand paper.

(3)    Galvanometer should be very sensitive.

(4)    Throughout the experiment  press key K₂(battery key) first and then key K₁(galvanometer key).

For more details view Video.

POST OFFICE BOX