A charged insulator disc is under induction. Will there be a torque on its center? Perhaps one could use Faraday’s law to compute the torque. But is Faraday’s law valid for this application? Nevertheless, let us compute with Faraday’s law.

Please read the article at
Faraday’s torque experiment
http://pengkuanem.blogspot.com/2012/11/faradays-torque-experiment.html
or http://www.academia.edu/2173815/Faradays_torque_experiment

Faraday’s law gives EMF as the voltage measured across the 2 terminals (A and D in Figure 1) of a loop under the induction of a varying magnetic field. Partial voltage between 2 intermediate points in the loop does exist, but is impossible to measure with a voltmeter. In Figure 1, a voltmeter connected to two arbitrary points B and C, will read the voltage induced by the magnetic field passing through the surface in grey. If the surface is reduced to zero, the voltmeter would read 0. This is why no study of partial voltage exists until now. I propose here an experiment to measure the partial voltage.

Please read the article at
Partial EMF measurement
http://pengkuanem.blogspot.com/2012/11/partial-emf-measurement.html
or
http://www.academia.edu/2075792/Partial_EMF_measurement