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PHYSICS LAB. VERNIER CALLIPERS. It consists of 1.Main Scale (graduated in cm/mm) 2.Vernier Scale. *Least count is the minimum possible length, that can be measured from that apparatus. *If N div. Of V.S. are equal in length to (N-1) M.S.div. Then L.C.=1M.S.-1V.S.
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VERNIER CALLIPERS It consists of 1.Main Scale (graduated in cm/mm) 2.Vernier Scale
*Least count is the minimum possible length, that can be measured from that apparatus. *If N div. Of V.S. are equal in length to (N-1) M.S.div. Then L.C.=1M.S.-1V.S. [ 1-(N-1)/N ] ms =1ms/N *Reading of Vernier Caliper will be: M.S. reading + (V.S. reading*L.C.)
ZERO ERROR • Positive error • Negative error • Corrections are done opposite to the error.
Screw gauge • There are two scales: 1.Main scale, graduated along the axis of the screw. 2.Cap scale/Head scale (H).
PRINCIPLE: The linear distance moved by the screw head is directly proportional to the amount of rotation given to the screw. • Distance moved on sleeve by screw, after giving one complete revolution is called Pitch. • Let there be ‘N’ divisions on circular scale and on ‘n’ complete rotations screw shifts by one sleeve unit, then Least Count can be given by 1/(n*N).
Thus reading of micrometer can be given by M.S. reading + (C.S. reading*L.C.)
When Spindle touches Anvil, indicator of ‘0’ on circular scale should touch the main scale line at ‘0’. • If this doesn’t happen, we call it error (positive/negative).
If the Thimble is yet to reach ‘0’ on main scale, it is positive error and if it has passed that point, it is negative error. • Correction is made to satisfy error.
*What is the reading of this micrometer? Given that there are 50 divisions on circular scale. *What if the zero error is -0.25?
SPECIFIC HEAT OF LIQUID USING CALORIMETER • JUST GO THROUGH THE CHAPTER OF CALORIMETRY IN H.C.VERMA’S BOOK.THE PRINCIPLE OF CALORIMETRY IS SIMPLY APPLIED. • ERROR ANALYSIS CAN BE DONE BY THE GENERAL METHOD.
OHM’S LAW V=I/RDR/R=DV/V+DI/I
METER BRIDGE • P/Q = L1/(100- L1) • ERROR • END-CORRECTION
POST OFFICE BOX S = (P/Q) x R • S=(P/Q)xR
FOCAL LENGTH OF A CONCAVE MIRROR AND A CONVEX LENS(u-v method) • Formulae :- • mirror : (1/f)=(1/v) + (1/u) • Lens : (1/f)=(1/v) + (1/u) Generalizing, the slope of (1/IvI) vs. (1/IuI) gives a straight line, whose intercept equals (1/IfI). • GIVEN u, v from experimental data, f can be calculated. • ERROR: take log and then differentiate.
Searle’s method for finding Young’s Modulus • Finding the slope of stress vs. strain graph, tan θ = l/W=l/mg • Stress = mg/Лr2 • Strain = l/L • Y=stress/strain = L/(Лr2 tan θ) • ERROR