#### To determine the velocity of a pulse propagated through a stretched spring/slinky - Science Practicals

Aim
To determine the velocity of a pulse propagated through a stretched spring / slinky.

Theory
Wave motion: The transference of energy in a given medium due to oscillatory motion of the particles of that medium about the mean position is known as wave motion.
Pulse: A wave produced by a single disturbance in a given medium is known as pulse.
Wavelength (Î»): The distance covered by one complete rarefaction and one complete compression or distance between two consecutive compressions or rarefactions.
Frequency: The number of vibrations made by a particle in the slinky per unit time (one second) is called its frequency.
Materials Required
A flat wire coiled spring/slinky of copper, a metre rod, a stopwatch and a small wooden board or a hard bound book.

Procedure
For Transverse Wave
Step 1: Take a slinky and place it lengthwise on the smooth surface of the table.
Step 2: Tie one end of the slinky with the fixed hook.
Step 3: Hold the free end of the slinky and stretch it (1 to 3 m depending upon the nature of slinky).
Step 4: Move your hand periodically and uniformly at right angles to the length of the slinky.
Step 5: Observe the  propagation of the wave through the slinky and observe  the formation of crests and troughs.

For Longitudinal Wave
Step 1: Compress the free end of the slinky periodically and observe the slinky.
Step 2: Measure the wavelength by measuring the distance between two consecutive troughs (T and T) or two crests (C and C) in case of transverse wave. In case of longitudinal wave, Î» is equal to distance between two consecutive compressions (C and C) or rarefactions (R and R).
Step 3: Note the time as pulse (wave) passes through slinky for a particular distance from which we can find out the velocity of the wave.

Result
Velocity of pulse =    m/s
• For the same slinky, the velocity of pulse will increase if it is stretched more and vice versa.

Precautions
1. The slinky should be a flat wire of copper.
2. Measure the distance between points A and B very accurately.
3. Do not stretch the slinky backward for more than 10 cm.
4. Give a very sharp push to generate pulse.
5. Make sure that you arrest push by a wooden block or a hard bound book, so that it does not overshoot point A.
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