An electric generator is based on the principle that when a conducting coil rotates in the magnetic field, an electric current is generated. It converts mechanical energy to electrical energy.
Armature is the rotating part of the generator. Armature is connected to commutator which is a cylindrical in shape and rotates with it. It also connects the armature to the external circuit by brushes.
"Most collisions are inelastic because the collision forces cause energy of motion to be transformed into sound, light and thermal energy", the given statement is true about elastic and inelastic collisions. ("perfectly elastic" and "totally inelastic")
Answer: Option D
Collisions or interaction of two or more objects with each other can be classified as elastic collision and inelastic collision. In elastic collision, there is no change in the kinetic energy of the object or the velocity and mass of the objects after collision. This is because most of the elastic collisions occur in terms of non-contact force.
But the inelastic collision occurs when there is change in the kinetic energy of the objects after collision. So mostly inelastic collision leads to striking between the objects and one object getting sticked to another object leading to perfectly inelastic collision.
Thus the inelastic collision occurring due to contact force leads to decrease in kinetic energy as most of kinetic energy or energy causing the motion has to be transformed into sound, light and thermal energy when collided with other molecules. Thus, the last statement is true about collisions.
The main function of a voltage transformer is to change alternating current (ac) voltage from one voltage level to another. The relationship between the primary coil and secondary coil of a transformer is a function of ratio of the voltage or current and number of turns or loop. The ratio of the voltages between the two coils is equal to the ratio of number of loops in the two coils.
Varying the number of winding in the primary and secondary coils allows the transformer to step-up or step-down voltages while power is neither increased nor decreased in the primary or secondary except for some minor losses such as iron losses, copper losses, hysteresis losses, eddy current losses, stray loss, and dielectric losses. Therefore, the power in the primary and secondary are the same. The power supplied to the 20-ohm resistor terminal in the secondary coil will be 400 Watts.