Spherometer
Spherometer
A spherometer is an instrument for the precise measurement
of the radius of curvature of a spherical surface.
It consist of a base circle of
three outer legs; & a center leg, which can be raised or lowered.
Pitch - It is the
distance between two consecutive threads of a screw
or It is
the distance moved in one rotation by screw.
zero Error - When the central leg touches the same surface
as the other three legs are; & if zero of the circular scale does not coincide
with the zero of the main scale then the instrument have zero error.
It is of two types-
It is of two types-
(i) Positive zero error= “0” of the circular scale lies
below the "0” of the main scale.
(ii) Negative zero error= “0” of the circular scale lies above
the "0” of the main scale.
Total Reading(R)
Where L = the distance between the any two legs.
h = height of curve surface from center
leg.
Correct reading = total reading + Error
Ammeter - An ammeter is a measuring instrument used to
measure the electric current in a circuit. It must be connected in series.
Voltmeter – A voltmeter is an instrument used for measuring
electric potential difference between two points in an electric circuit. It
must be connected in parallel.
