Answer:
The pH scale was invented by Svante Arrhenius is false.
Explanation :
because the pH scale was invented by Soren Sorensen
Answer:
Commutator is a ring which reverse the direction of current in AC circuit so that the coil connected to it will continuous to move in the same direction.
Explanation:
In motors there exist a coil which is rotated due to torque of magnetic field when current flow through it. Since AC current is used to run the motor so we know that AC current changes its direction after half cycle.
So here commutator plays an important role to reverse the direction of current after every half cycle so that the current goes in same direction always into the coil.
This will produce a constant direction torque on the coil so that it will rotate in same sense always.
So commutator role is to provide same direction current to the coil by reversing its direction after every half cycle
Answer: the reaction force is large.
Explanation:
From Newton's third law, we know that for every action, there is equal and opposite reaction.
Since, a large amount of high speed of water is ejecting out from hose. The high momentum due to large speed in short duration of time would cause water to eject out with great force. The reaction force would act on the firefighter holding the hose. An equal amount of large force would act on him. Thus, it is difficult for a firefighter to hold a hose that ejects large amounts of high speed water.
Answer:
False
Explanation:
Sun mass is dominating in Solar system as compared to other planets, asteroids and comets. Sun itself accounting for the 99.9% of the mass of the solar system. Hence the gravitational force exerted by the Sun dominates the other objects in the solar system. So we can conclude that solar system has non-uniform composition. The given statement is false
