General Knowledge

Lenz’s Law

The induced emf (current) is always in such a direction as to oppose the change that caused it.

1. Induced emf and induced current act in the same direction

2. Induced current is caused by the movement of the rod relative to the B-field

3. Energy is conserved

4. To gain electrical energy we have to lose kinetic energy

Kepler’s Law

1. The path of the plants about the sun is elliptical in shape, with the center of the sun being located at one focus

2. An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal area in equal intervals of time

3. The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun (T²/r³ = constant)