Experiment:1 Concave mirrorDate:Aim: To determine the focal length of a given concave mirrorApparatus: The given concave mirror, mirror stand, optic screen, light source with wire gauze, metre scale, etc.,Formula : 1 1 1 = + f u v

f = focal length ; u = object distance ; v = image distance;Ray diagram : Sample Graphs: Observation: Focal length of the mirror by distant object method = cmS.No.u cmv cmf = uv / u+ v cm1/u cm-11/v cm-1

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Procedure: Keep the mirror on the mirror stand. Keep the mirror mounted stand facing the door or window of your lab. Keep the optic screen in front of the mirror. Adjust the position of the screen such that you can see a clear image of a distant object say a tree/building on the screen. Measure the distance between the screen and the mirror with a metre scale. Note down this value as f. Double this value and write the 2f value as the middle value of u column. Write three values of u greater than 2f and write three values of u lesser than 2f in the u column (in ascending order). Switch on the light source. Now by keeping the light source at the first position as marked on u column adjust the position of the screen by the side of the light source to get the clear image of the wire gauze on the screen. Measure the distance between the screen and the mirror and note down the same as image distance v against the first value of u . Repeat the experiment for the remaining u values one by one. Calculate the f value by using the formula f = uv/ u+v in each case and record them. Find the average f value. Find the values of reciprocals of u and v and record them in the observation table. Draw a graph between u and v with suitable but same scales and origin for both x and y axes. The graph will be a hyperbola. Draw the angular bisector of the angle between x and y axes. This will meet the graph at a point whose coordinates are equal which is equal to 2f. Find f from this 2f and record. Draw another graph between 1/u and 1/v with suitable scales. It will be a straight line which will intercept the x and y axes at almost same values. These intercept values will be equal to 1/f. Calculate f from each intercept and get the average f and record the values. Write the values of f in the result.

Result: The focal length of the given concave mirror is found to be (i) By distant object method = cm(ii) By u v method = cm(iii) From u v graph = cm (iv) From 1/u 1/v graph = cm

Sources of error:1.Parallax error may occur in measurements. 2.Better clarity of image may be possible. 3.Position of mirror and screen may have more deviation of light path

Precautions : 1.Avoid parallax error in measurements 2. Try for maximum clarity of image each time and select the best. 3. The image formed on the screen must be closer to the source side.Experiment : 2 Convex lensDate :Aim: To determine the focal length of a given convex lensApparatus: The given convex lens, lens stand, optic screen, light source with wire gauze, metre scale, etc.,Formula : 1 1 1 On application of sign conventions = - the formula will become f v u f = uv/ u+v

f = focal length ; u = object distance ; v = image distance;Ray diagram :

Observation: Focal length of the given lens by distant object method = cmS.No.u cmv cmf = uv / u+ v cm1/u cm-11/v cm-1

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Procedure: Keep the lens on the lens stand. Keep the lens mounted stand facing the door or window of your lab. Keep the optic screen on the other side of the lens such that the light from the window or door will pass through the lens and form an image of a distant object. Adjust the position of the screen such that you can see a clear image of the distant object say a tree/building on the screen. Measure the distance between the screen and the lens stand with a metre scale. Note down this value as f. Double this value and write the 2f value as the middle value of u column. Write three values of u greater than 2f and write three values of u lesser than 2f in the u column (in ascending order). Switch on the light source. Now by keeping the light source at the first position as marked in u column, from the lens, adjust the position of the screen on the other side to get the clear image of the wire gauze on the screen. Measure the distance between the screen and the lens and note down the same as image distance v against the first value of u . Repeat the experiment for the remaining u values one by one. Calculate the f value by using the formula f = uv/ u+v in each case and record them. Find the average f value. Find the values of reciprocals of u and v and record them in the observation table. Draw a graph between u and v with suitable but same scales and origin for both x and y axes. The graph will be a hyperbola. Draw the angular bisector of the angle between x and y axes. This will meet the graph at a point whose coordinates are equal which is equal to 2f. Find f from this 2f and record. Draw another graph between 1/u and 1/v with suitable scales. It will be a straight line which will intercept the x and y axes at almost same values. These intercept values will be equal to 1/f. Calculate f from each intercept and get the average f and record the values. Write the values of f in the result.Result: The focal length of the given convex lens is found to be (i) By distant object method = cm(ii) By uv method = cm(iii) From uv graph = cm (iv) From 1/u 1/v graph = cm

Sources of error:1.Parallax error may occur in measurements. 2. Better clarity of image may be possible. 3. Centres of the lens and source may not be aligned.

Precautions : 1.Avoid parallax error in measurements 2. Try for maximum clarity of image each time and select the best. 3.See that the centres of the source and the lens are aligned.Experiment : 3 Concave lensDate :Aim: To determine the focal length of a given concave lens using a convex lens.Apparatus: The given concave lens, a convex lens, lens stand, optic screen, light source with wire gauze, metre scale, etc.,Formula : 1 1 1 1 1 1 = + & = + f u v F f1 f2(After application of signs)

f = focal length ; u = object distance ; v = image distance; F = focal length of the combined lenses; f1 = focal length of convex lens f2 = focal length of the concave lensRay diagram :

Observaion: Convex lens Combined lensesS.NoU cm V cmf1= uv/u+v (cm)

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S.NoU cm V cmF = uv/u+v (cm)

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Procedure: Keep the convex lens on the lens stand. Keep the light source on one side and the optic screen on the other side of the lens. Switch on the light. By keeping the object distance a particular selected value, adjust the position of the screen such that you can see a clear image of the wire gauze on the screen. Measure the image distance i.e., between the screen and the lens with a metre scale. Note down the values of u and v in the table. Repeat the experiment for four more values of u and measure image distance v in each case and record the values. Calculate the f1 value by using the formula f = uv/ u+v in each case and record them. Find the average f1 value. Now by combining the convex lens and the concave lens by a rubber band place the combination on the lens stand. Repeat the experiment for determination of image distances for five different object distances as you did for the convex lens. Note down the values in the tabular column.Calculate the F value in each case and record. Find the average F. By using the formula 1/F= (1/f1)+(1/f2) calculate the focal length f2 of the concave lens Result: The focal length of the given convex lens is found to be = cm The focal length of the combination of lenses is found to be = cm The focal length of the given concave lens is found to be = cm

Sources of error:1.Parallax error may occur in measurements. 2. Better clarity of image may be possible. 3. Centres of the lens and the source may not be aligned.

Precautions : 1. Avoid parallax error in measurements 2. Try for maximum clarity of image each time and select the best. 3. See that the centres of the lens and the source are aligned time

Experiment : 4 Convex MirrorDate :Aim: To determine the focal length of a given convex mirror using a convex lens.Apparatus: Given convex mirror, convex lens, mirror stand, lens stand, light source, metre scale, optic screen etcFormula : f = R/2 where f is focal length and R is radius of curvatureRay diagram: Observation:

S.No R cmf = R/2 cm

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Mean f = cmProcedure: Mount the given convex lens in its lens stand. Keep the light source on one side of the lens stand and the optic screen on the other side. By keeping a selected object distance adjust the optic screen to get the clear sharp image of the wire gauze. Mount the convex mirror on its stand. Introduce the convex mirror in between the lens and the optic screen such that its reflecting surface is facing the lens. Adjust the position of the mirror such that the final image is formed on the source box itself. Adjust the mirror position till you get a clear sharp image. Take care that you do not disturb the lens or screen or source. Measure the distance between the mirror and the screen. This distance is R the radius of curvature. Repeat the experiment for different positions of lens from the source and record the values. Calculate f value by using the formula f = R/2 and record the values. Find the average f.

Result: The focal length of the given convex mirror is found to be = cm

Sources of error:1.Parallax error may occur in measurements. 2. Better clarity of image may be possible. 3. Centres of the lens and the source may not be aligned.

Precautions : 1. Avoid parallax error in measurements 2. Try for maximum clarity of image each time and select the best. 3. See that the centres of the lens and the source are aligned

Experiment : 5 Glass slabDate:Aim: To determine the refractive index of a given glass slab by using travelling microscope.Apparatus: Given glass slab, travelling microscope, lycopodium powder, etcFormula : = Real depth/ Apparent depth where is the refractive index of the glass slabObservation:1 Main Scale Division = 0.5 mm1 Vernier Scale Division= 0.49 mmLeast count = 1MSD 1VSD = 0.5 0.49 = 0.01 mm = 0.001 cm

Observation madeMSRcmVC

TRcmReal depthcmApparent depth cm= RD/AD

Direct view

Through slab

Surface of slab

Procedure: Adjust the eyepiece and cross wire for clear vision. Mark a dark point on the white platform of the microscope. Adjust the microscope to view the clear image of the point through it. Arrest the microscopes vertical movement by screwing the adjustment screw. Use the vertical fine adjusting screw for the clear image of the point. Note down the main scale reading and vernier coincidence on the vertical scale for this direct view of the point. Now place the given glass slab on the point. Slowly raise the microscope up by releasing the vertical scale locking screw. Adjust the position of the microscope till you get the clear image of the point seen through the slab. Lock the

Result: The focal length of the given convex mirror is found to be = cm

Sources of error:1.Parallax error may occur in measurements. 2. Better clarity of image may be possible. 3. Centres of the lens and the source may not be aligned.

Precautions : 1. Avoid parallax error in measurements 2. Try for maximum clarity of image each time and select the best. 3. See that the centres of the lens and the source are aligned

Experiment : 6 Glass PrismDate:Aim: To determine the refractive index of a given glass prism by drawing its i-d curve Apparatus: Given glass prism, drawing sheet, drawing board, protractor, pencil etc., Formula: Sin (A+d) = 2 Sin (A/2)

where is the refractive index of the glass prism, A is the angle of the prism, d is the minimum deviation of the prismObservation:Observation:S.no i d

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Procedure: Adjust the eyepiece and cross wire for clear vision. Mark a dark point on the white platform of the microscope. Adjust the microscope to view the clear image of the point through it. Arrest the microscopes vertical movement by screwing the adjustment screw. Use the vertical fine adjusting screw for the clear image of the point. Note down the main scale reading and vernier coincidence on the vertical scale for this direct view of the point. Now place the given glass slab on the point. Slowly raise the microscope up by releasing the vertical scale locking screw. Adjust the position of the microscope till you get the clear image of the point seen through the slab. Lock the

Result: The focal length of the given convex mirror is found to be = cm

Sources of error:1.Parallax error may occur in measurements. 2. Better clarity of image may be possible. 3. Centres of the lens and the source may not be aligned.

Precautions : 1. Avoid parallax error in measurements 2. Try for maximum clarity of image each time and select the best. 3. See that the centres of the lens and the source are aligned

Experiment No: 7 Ohms Law Date:Aim: To find the resistance per unit length of a given wire using Ohms lawApparatus Required: Given wire, ammeter, voltmeter, connecting wires, rheostat etc.,Ohms Law: At a constant temperature, the current passing through a wire is directly proportional to the potential difference across the wire.Circuit diagram:

Observation: Least count of the voltmeter = volt Least count of the ammeter = ampereS.No.V voltI ampereR = V/I

1 2 3 4 5 6

I (ampere)

V(volt)

Procedure: Connect the circuit as shown in the circuit diagram. Switch on the circuit. Adjust the rheostat to get a readable current in the ammeter. Note down the ammeter and voltmeter readings. Repeat the experiment for different volt and current values. Calculate the resistance in each case by using the formula R = V/I and record the values. Find the average R. Draw a graph between V and I. Find the slope of the line in the graph. This slope is also equal to R. Calculate the resistance per unit length of the wire after measuring the length of the wire. Record the values. Result: The resistance of the wire = Resistance per unit length of the wire = /cm

Sources of error: 1.Parallax error may occur 2.Connections may be loose. 3.Wire may be heated up

Precautions: 1. Avoid parallax by looking perpendicular to the dials of the voltmeter and ammeter. Use the mirror provided inside the meters to avoid parallax. 2. Check for tight connections 3. Avoid heating up of the wire by passing the current for only a very Short duration in each trial.

Experiment No: 8 Potentiometer : E1/E2Date:Aim: To find the ratio between two primary cells by using potentiometerApparatus : Potentiometer, galvanometer, high resistance, given primary cells, DPDT switch, DC source, high resistance, connecting wires etc.,Formula : E1 = l1 E2 l2

Circuit diagram:

Observation: S.No.l 1cm l2cm E1 = l1 E2 l2

1 2 3 4 5 6

Procedure: Connect the circuit as shown in the diagram. Switch on the source. Push the DPDT switch to cell 1 side. Check for opposite deflections in the galvanometer, by touching the first and the last wires of the potentiometer with the jockey. If it is not with opposite deflections, check for the correctness of the connections.If it shows opposite deflections then find the balancing lengths for the cells separately one by one. Record the balancing lengths in the tabular column. Repeat the experiment by adjusting the rheostat. Record the values. Calculate l1 / l2 in each case and record the values. Find the average value of l1 / l2. This is the ratio of the emfs of the cells

Result: The ratio of emfs of the given cells is found to be =

Sources of error: 1.There may be loose connections2.Parallax error may occur in measurement3.Number of the wire in which the balancing point is taken may go wrong Precautions: 1.Avoid parallax 2. Check for tight connections 3.Count the number of the wire in which the balancing point is observed