Page 48 - Physics - XI

3 Oscillations
Oscillations

EXPERIMENT - 7

Aim
Using a simple pendulum, plot its L-T graph and use it to fi nd the eff ective length of second's pendulum.
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Apparatus and Materials Required
Clamp stand, split cork, Vernier Calliper, stopwatch, metallic spherical bob (brass/iron) with a hook, strong
cotton thread/string, metre scale, graph paper, eraser, and a pencil

Description of Time Measuring Devices

1. Stopwatch: A stopwatch is a special kind of watch which is used to measure the time elapsed for a
particular event. It has two dials. The smaller dial has minute's hand and the bigger dial has second's
hand. There is a multipurpose knob at the top. This knob has start/stop/back to zero function. There are
30 equal divisions in the smaller dial and each division represents 0.1 s. The least count of a stopwatch
is 0.1 s.

Fig. 7.1: Stopwatch
2. Stop clock: A stop clock is less accurate than a stopwatch. The least count of a stop clock is 1 second.

Fig. 7.2: Stop Clock

Terms and Definitions

Simple Pendulum
An ideal simple pendulum consists of a heavy point mass (bob) suspended by a weightless, inextensible,
and perfectly fl exible string from a rigid support. However, these conditions cannot be achieved practically.

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