Which of the following factors will increase the sensitivity of moving coil meter?

A moving coil meter works by measuring the magnetic field produced by an electric current passing through a coil of wire. The sensitivity of the meter refers to how easily it can detect small changes in the current. A strong spring, which opposes the motion of the meter's pointer, will actually decrease the sensitivity of the meter, making it less responsive to small changes in current. A low number of turns on the coil or a small area of the coil will also reduce sensitivity, since there will be less magnetic field produced for a given current. Therefore, the factor that will increase the sensitivity of a moving coil meter is a soft iron core. This is because a soft iron core will amplify the magnetic field produced by the current, making it easier to detect small changes. The iron core will also help to concentrate the magnetic field, further increasing the sensitivity of the meter.