Question Detail

Page 20 applies Lenz's Law: 'there is less inward flux through the loop. Hence the induced current gives inward flux. ⇒ So the induced current is clockwise.' This is referring to the change in flux. As the loop moves into the Bx field, the inward flux increases. To oppose this increase, the induced current must create an outward flux. Using the right-hand rule, an outward flux would be created by a counter-clockwise current. However, the explanation states 'less inward flux' if removing it, and a clockwise current would create inward flux. Let's re-evaluate based on the image on page 17 where the loop is entering the field, increasing inward flux. Lenz's law says the induced current will oppose this change. To oppose an increase in inward flux, the induced current must create an outward flux. By the right-hand rule, a counter-clockwise current creates an outward magnetic field. So, the text 'Hence the induced current gives inward flux. ⇒ So the induced current is clockwise.' on page 20 seems to imply the arrow V is moving out of the field, or the text is simplified for a particular scenario not explicitly shown. However, following the derivation from page 19, dB / dt = -BDv. This implies the flux is decreasing (v is positive, moving to the right, which could mean moving out of the field, or the x is defined such that increasing x means less flux). If the inward flux is decreasing (e.g., loop leaving the field), Lenz's Law states the induced current will try to maintain the inward flux, so it would create inward flux, meaning a clockwise current. Given the options and the explanation, the document implies the clockwise direction for some scenario related to the change. The text on page 20 explicitly says 'Lenz's law: there is less inward flux through the loop. Hence the induced current gives inward flux. So the induced current is clockwise.' This implies the scenario being considered at that point is one where inward flux is decreasing (e.g., the loop is moving out of the field to the right, or 'x' is defined such that moving right means 'less inward flux'). If the inward flux is decreasing, Lenz's law dictates an induced current that generates an inward flux, which corresponds to a clockwise current (by right-hand rule).