Explanation:
If a coil of wire is placed in a magnetic field and rotated, an alternating (sinusoidal) current is induced. As it rotates, sometimes it is cutting through lots of magnetic flux, and so lots of current is
induced.
At other times, it is moving parallel to
the flux, and so no flux is cut, and no current is induced. In between, some current is induced. This creates an alternating current. Either end of the coil can be connected to wires outside of the generator in order to use the current elsewhere. This would be fine for the
first few rotations, but after this, the wires would get tangled up and the generator would be useless. To avoid this, we use a commutator. In an AC generator, this is a pair of rotating conducting 'slip rings' attached to either end of the coil. Carbon brushes bring these into contact with the outside world.
Answer:
a) Watt is a derived unit because it's not a “base unit.”
b) The atomic clock is suitable for measuring time because natural atomic oscillations happen at a higher frequency and as a result they are more stable.
c) There is fluctuation in time measured by a pendulum clock because the pendulum rod changes in length slightly with changes in temperature, causing changes in the rate of the clock. An increase in temperature causes the rod to expand, making the pendulum longer, so its period increases and the clock loses time.
D) The weight of an object is more at pole and less at equator of the earth because the distance of the pole is less than the distance of the equator from the centre of the earth.
e) The weight of an object on the moon is about one-sixth the weight it would have on the earth because the moon's gravitation force is determined by the mass and the size of the moon. Hence, the weight of an object on the moon is 1/6th its weight on the earth.
Liquid is not a solid object so make sure you define them
