Answer:
All of the above
Explanation:
The correct answer is option E (All of the above)
All the options are alternative source of energy.
The option given are not the traditional way (energy production from coal) of extracting energy as the loss of natural resources does not take place in these source of energy.
energy extracted from wind, solar light , hydrogen ,etc are the source of energy the alternative source of production of energy because do not exploit the natural resources, reduce the carbon emission and energy produced by them is clean energy.
30 grams of radioactive isotope have passed.
There are some missing information in the question.
However, since you are talking about magnetic force, I think you refer to the Lorentz force. When a particle of charge q and velocity v is immersed in a magnetic field of intensity B, the force acting on the particle is:

where

is the angle between the magnetic field and the direction of the particle.
Therefore, if force F is doubled, then also the velocity v must be double of its initial value:
Answer:
The answer is: B. -487 ..............
The energy stored by a system of capacitors is given by

where Ceq is the equivalent capacitance of the system, and V is the voltage applied.
In the formula, we can see there is a direct proportionality between U and C. This means that if we want to increase the energy stored by 4 times, we have to increase C by 4 times, if we keep the same voltage.
Calling

the capacitance of the original capacitor, we can solve the problem by asking that, adding a new capacitor with

, the new equivalent capacitance of the system

must be equal to

. If we add the new capacitance X in parallel, the equivalent capacitance of the new system is the sum of the two capacitance

and since Ceq must be equal to 4 C1, we can write

from which we find