Chapter 20. Faraday’s law of induction (20-2)

Question

+7Ws4hBdM8rNwM9yHasPvDK7phih1VAdGXOL/FqgnYHJ1pvrjurKDZ/3ZwLt9EJiBh9P/FiTnuc=
{"title":"Magnitude of the induced or motional emf in a loop","description":"Correct!","type":"correct","color":"#99CCFF","code":"[{\"shape\":\"poly\",\"coords\":\"82,133\"},{\"shape\":\"rect\",\"coords\":\"10,16,12,16\"},{\"shape\":\"poly\",\"coords\":\"144,22\"},{\"shape\":\"rect\",\"coords\":\"14,66,43,102\"}]"} {"title":"Change in the magnetic flux through the surface outlined by the loop","description":"Wrong","type":"incorrect","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"183,6,232,53\"}]"} {"title":"Time interval over which the change in magnetic flux takes place","description":"Incorrect","type":"incorrect","color":"#333300","code":"[{\"shape\":\"rect\",\"coords\":\"205,97,233,136\"}]"}

Question

FPeOmm2Hkz2wFl0xHELnGBC9huajwH7VTtuOd0t2RAKfW7pjGlA+oZugm54VJIhYmmIg8QhZ/4G9YI/6PzKHf+IUEznzfl10
{"title":"Magnitude of the induced or motional emf in a loop","description":"Wrong","type":"incorrect","color":"#99CCFF","code":"[{\"shape\":\"poly\",\"coords\":\"82,133\"},{\"shape\":\"rect\",\"coords\":\"10,16,12,16\"},{\"shape\":\"poly\",\"coords\":\"144,22\"},{\"shape\":\"rect\",\"coords\":\"14,66,43,102\"}]"} {"title":"Change in the magnetic flux through the surface outlined by the loop","description":"Correct!","type":"correct","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"183,6,232,53\"}]"} {"title":"Time interval over which the change in magnetic flux takes place","description":"Incorrect","type":"incorrect","color":"#333300","code":"[{\"shape\":\"rect\",\"coords\":\"205,97,233,136\"}]"}

Question

ANTPJu2UK12DFGKgtM+5KPaaQmVuFNmz8cvIsPUcAJzn066Q9COL4SAbkP4g7I6UdYuDv9Fkrr+XKkWFM6/y97cSEOE=
{"title":"Magnitude of the induced or motional emf in a loop","description":"Wrong","type":"incorrect","color":"#99CCFF","code":"[{\"shape\":\"poly\",\"coords\":\"82,133\"},{\"shape\":\"rect\",\"coords\":\"10,16,12,16\"},{\"shape\":\"poly\",\"coords\":\"144,22\"},{\"shape\":\"rect\",\"coords\":\"14,66,43,102\"}]"} {"title":"Change in the magnetic flux through the surface outlined by the loop","description":"Incorrect","type":"incorrect","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"183,6,232,53\"}]"} {"title":"Time interval over which the change in magnetic flux takes place","description":"Correct!","type":"correct","color":"#333300","code":"[{\"shape\":\"rect\",\"coords\":\"205,97,233,136\"}]"}

Review

This law states that the magnitude of the emf that appears in a loop is equal to the magnitude of the rate of change of the magnetic flux through the loop. If a large change in flux \(\Delta{\Phi_B}\) happens in a short time interval \(\Delta{t}\), the resulting emf has a large magnitude; if the change in flux is relatively small and happens over a long time interval, the resulting emf has a small magnitude.

Note that Equation 20-2 tells us only the magnitude of the emf, not its direction. In the following section we’ll see how the direction is determined.