EASY
Upper Secondary: IGCSE
IMPORTANT
Earn 100
A current flows downward in a wire that passes vertically through a small hole in a table-top. Will the magnetic field lines around it go as seen from above?
Important Questions on Electromagnetic Forces
EASY
Upper Secondary: IGCSE
IMPORTANT
Observe the following figure.
How can you tell from the pattern that the field gets weaker as you get further from the wire?
MEDIUM
Upper Secondary: IGCSE
IMPORTANT
Look back at the diagram of the relay shown in the figure below.
Why is the coil fitted with a soft iron core?
EASY
Upper Secondary: IGCSE
IMPORTANT
Consider the figure given below.
Suppose that the two magnets were turned around so that there was a magnetic north pole on the left. Explain how the coil would move.
MEDIUM
Upper Secondary: IGCSE
IMPORTANT
In a D.C. motor, why must the current to the rotor coil be reversed twice during each rotation?
EASY
Upper Secondary: IGCSE
IMPORTANT
What device reverses the current in a DC motor?
EASY
Upper Secondary: IGCSE
IMPORTANT
Describe how the turning effect of a d.c. motor will change if the current flowing through the motor coil is increased.
EASY
Upper Secondary: IGCSE
IMPORTANT
List two ways to reverse the force on a current-carrying conductor in a magnetic field.
EASY
Upper Secondary: IGCSE
IMPORTANT
For Fleming's left-hand rule, write down the three things that are to each other, and next to each one write down the finger or thumb that represents it.
