Question

A galvanometer can be converted into a voltmeter by connecting:
(A) A high resistance in series with the galvanometer
(B) A high resistance in parallel with the galvanometer
(C) A low resistance in series with the galvanometer
(D) A low resistance in parallel with the galvanometer

Answer 1

Galvanometer is an instrument for estimating a little electrical flow or a component of the flow by deflection of a moving loop. The deflection is a mechanical rotation gotten from forces coming about because of the current.

Complete step by step answer:
-When put in an external magnetic field, the current-carrying coil feels a magnetic torque. The angle at which the coil is deflected due to the influence of the magnetic torque is equal to the amplitude of the current in the coil.
-The moving coil galvanometer is a rectangular coil that has numerous turns and it is typically made of meagerly protected or fine copper wire that is wound on a metallic casing. The coil is allowed to turn about a fixed axis. A phosphor-bronze strip that is associated with a versatile torsion head is utilized to suspend the coil in a uniform spiral attractive field.
-Basic properties of the material utilized for suspension of the loop are conductivity and a low estimation of the torsional constant. A cylindrical shaped soft iron centre is evenly situated inside the loop to improve the quality of the attractive field and to make the field spiral. The lower some portion of the loop is connected to a phosphor-bronze spring having few turns. The opposite finish of the spring is associated with restricting screws.
-Since Galvanometer is an exceptionally sensitive instrument, accordingly it is not used for measuring high values. So as to change over a Galvanometer into voltmeter, an exceptionally high resistance is connected in series with the galvanometer.

Hence, option A is correct.

Note: A galvanometer can only detect the direction of current. If it is used to measure large current then the galvanometer will be damaged.