• summary_type: application
• word_count: 160

T = 2pisqrt(L/g) gives g = 4pi^2L/T^2. Effective length L = string length + bob radius. Measure T by timing 20-50 oscillations (reduces human reaction time error). Plot T^2 vs L: straight line through origin, slope = 4pi^2/g. Error propagation: Delta_g/g = Delta_L/L + 2Delta_T/T — timing error is amplified by factor 2. Keep amplitude < 5 degrees (otherwise T depends on amplitude). Use a long string for longer T (easier to measure accurately). Precautions: rigid support, no air drafts, thin inextensible string, measure from pivot to bob center. If the T^2-L graph doesn't pass through origin, it indicates a systematic error in length measurement. The y-intercept gives the effective length correction. Simple pendulum is the most common JEE experimental question — understanding error analysis and graphical interpretation is essential.