Question

Magnetic field intensity is measured by a
A. Thermopile
B. Flux meter
C. Pyrometer
D. Thermometer

Answer 1

As we know , Magnetic field is a physical vector quantity which has its influence on electric charges specially when a moving charge enters in presence of magnetic field, it gets deflected. A charge when enters in a magnetic field with some velocity it always experiences a force which is perpendicular to its velocity and magnetic field.

Complete answer:
In electromagnetics, the term magnetic field is used for vector fields denoted by symbols $B$ and $H$. Magnetic field strength is measured in SI unit’s ampere per meter. Magnetic flux density is measured in tesla denoted by $T$ which in SI units is equivalent to Kilogram per second square per ampere which can be simply written as $kg\,{\sec ^{ - 2}}\,{A^{ - 1}}$.Here $A$ denotes for ampere.Magnetic field intensity is measured by a flux meter. It has very high electric damping and very low torque. Few advantages of flux meter are:
-The magnitude scale of the flux meter is always measured in Weber meters.
-The flux meter is portable and easy to use.

Hence, the correct option is B.

Note: Flux meter measures the magnetic field intensity in the units of Weber that can be written as volt-seconds. The only disadvantage of using the flux meter is that it is less sensitive and little less accurate than the ballistic galvanometer. But it’s highly preferred over other instruments.