Answer:
This is a paradox — an inconsistency that often leads people to think that time travel cannot occur in our universe." A variation is known as the "grandfather paradox" — in which a time traveler kills their own grandfather, in the process preventing the time traveler's birth
Explanation:
hope this Wil help ....
Out of that list, the concave mirror is the only item that can concentrate sunlight and heat into a small area. But if you could get ahold of a convex lens, that would be even better.
Answer:
The maximum electric power output is 
Explanation:
From the question we are told that
The capacity of the hydroelectric plant is 
The level at which water is been released is 
The efficiency is
0.90
The electric power output is mathematically represented as
Where
is the potential energy at level h which is mathematically evaluated as

and
is the potential energy at ground level which is mathematically evaluated as


So
here 
where V is volume and
is density of water whose value is 
So

substituting values


The maximum possible electric power output is

substituting values


Given Information:
Power = P = 100 Watts
Voltage = V = 220 Volts
Required Information:
a) Current = I = ?
b) Resistance = R = ?
Answer:
a) Current = I = 0.4545 A
b) Resistance = R = 484 Ω
Explanation:
According to the Ohm’s law, the power dissipated in the light bulb is given by

Where V is the voltage across the light bulb, I is the current flowing through the light bulb and P is the power dissipated in the light bulb.
Re-arranging the above equation for current I yields,

Therefore, 0.4545 A current is flowing through the light bulb.
According to the Ohm’s law, the voltage across the light bulb is given by

Where V is the voltage across the light bulb, I is the current flowing through the light bulb and R is the resistance of the light bulb.
Re-arranging the above equation for resistance R yields,

Therefore, the resistance of the bulb is 484 Ω