the hoover dam in the u. s produces 2 x 10 ^9 watts of electricity and is composed of 7 x 10^9 kg of concrete. concrete requires 1mj of energy to produce 1 kg
1) how much energy did it take to produce the dam?
2) how long is the "energy payback time" for the dam?
show your work.

(I). The energy is .

(II). The time is .

Step-by-step explanation:

Given that,

Power

Mass of concrete

Concrete requires 1 MJ of energy to produce 1 kg.

(I). We need to calculate the energy

Using formula of energy

1 kg concrete required 10⁶ J energy.

So, The energy is

The energy is .

(II). We need to calculate the time

Using formula of power

Put the value into the formula

Hence, (I). The energy is .

(II). The time is .

plants store their excess carbohydrate in the form of starch so that it could be used as energy source later on. the excess carbohydrate is converted into starch in the plastid i.e. chloroplast & this process occurs in the presence of sunlight. it is an insoluble polymer of glucose which gets stored in cell organelles named as amyloplasts. in some plants, starch is also stored in roots and embryos.