Question 1
An electrically heated pad is designed to keep a pet warm.
The pad is heated using a resistor that is placed inside the pad. The dimensions of the resistor are shown on the diagram. The resistor has a resistance of and a total length of 1.25 m .
When there is a current in the resistor, the temperature in the pad changes from a room temperature of to its operating temperature at .
Question (a)
(a)
When there is a current in the resistor, magnetic forces act between the resistor strips.
For the part of the resistor labelled RS,
Question (i)
(i)
outline the magnetic force acting on it due to the current in PQ .
Question (ii)
(ii)
state and explain the net magnetic force acting on it due to the currents in PQ and TU .