Power is the rate of work done given by dividing work done by time.Efficiency is the ratio of work output to work input
power input= 100 watts
power output = x
efficiency= 0.8
thus 0.8 = x/100, therefore x = 80
power is given by energy times time
hence time = 80/300000 = 0.00026 seconds
Time in hours = 0.00026/360 = 7.407 x 10 ∧7 hours
I think it might be D.) Group 17, period 5. but i'm not entirely sure<span />
Answer:
B) 2I
Explanation:
The equation that relates voltage, current and resistance is V=RI.
The equation for the resistance of a material in terms of its resistivity, length and cross-sectional area is 
In this case, the length is divided by 2 while keeping its resistivity (since it's the same material) and area, which means the resistance gets divided by 2. Then, looking at the equation I=V/R and keeping V constant, one deduces that since the resistance now is half than before then current now must be twice as before.
This is all intuitive in fact, cuting a homogeneous resistor in half and leaving the rest of the variables constant makes twice as easy for the electrons to cross the conductor, thus twice the current (one has to know that all the variables involved behave linearly, as the equations show).
C) The president submits the federal budget every year.
Hope this helps you!
The quest to put Americans on the moon before the Soviets do. During the Space Race, a couple of astronauts went up into space only to be tragically killed in an explosion.