Efficiency = useful energy out / total energy in x 100
= 100/400 x 100
=0.25 x 100
= 25%
25%
The answer is C hope this helps <span />
Answer:
<em>clockwise</em>
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Explanation:
when current flows through a ring in a clockwise direction, it produces the equivalent magnetic effect of a southern pole of a magnet on the coil.
Since the current is decreasing, there is a flux change on the lower ring; generating an induced current on the lower ring. According to Lenz law of electromagnetic induction, "the induced current will act in such a way as to oppose the motion or the action producing it". In this case, the induced current will have to be the same polarity to the polarity of the current change producing it so as to repel the two rings far enough to stop the electromagnetic induction. The induced current will then be in the clockwise direction on the lower ring.
Answer:
The pendulum with the greatest frequency is one with short length.
Explanation:
A simple pendulum is a device which consists of mass m hanging from the string of length L attached to the some point.When displaced and released its swings back and forth with periodic motion.
The frequency of simple pendulum is given by
f = 
where T is the time period.
f =1/2π√g/l
where , l is the length of pendulum
g is acceleration due to gravity.
The frequency of simple pendulum is defined as how much time or the distance covered by the bob in one second
From the given equation we can find that the frequency of the simple pendulum is<em> inversely proportional</em> to square root of length.Hence the frequency will be maximum if the length of the bob is short.