Three physical quantities will be measured in the experiment.

1. First, measure the spring constant of the spring. (Remember I^st semester experiment). Take readings in a table.
2. Attach the free end of the spring to the thread and pass it over the pulley.
3. Unscrew the disc attached to the rod and pass it through the lid of the clear acrylic cylinder. Attach 50gm weight to the rod. Now, screw the disc to its position. Calculate the natural frequency as
   Check if this frequency lies within the minimum, maximum range of the frequency of the external force. If not, change the mass and recheck.
4. Now, pour the liquid into the cylinder.
5. Place the scale (with magnetic rear) just behind the cylinder and see the scale through the cylinder. The scale appears to be magnified. If needed adjust the scale vertically or sideways so that the lower edge of the disc lies on the graduation of the scale.
6. Switch ON the Oscillator. The frequency can be changed by pressing the down/up switch.
7. Set the driving (external) frequency to 0.2 Hz.

Carefully observe the total displacement of the oscillator along the scale. Divide this by 2 to get the amplitude. Take readings in table III.

Carefully observe that the thread on both sides of the pulley should be in a single plane, else make adjustment.

7. Increase the frequency in steps of 0.2 Hz and measure the corresponding amplitude. Make sure to use the frequency values above and below the natural frequency.
8. Plot the graph – driving (external) frequency vs the amplitude.

Spring constant=

mass =

natural frequency =

9. Identify frequency corresponding to maximum displacement. This is resonant frequency. Compare it with natural natural frequency