Answer:
16km/h
Explanation:
Vt=20km/h ---train speed
Vd=4km/h
Donas speed relative to ground is:
Vrd=Vt-Vd
Donas is moving in opposite direction of train .
Vrd=20km/h-4km/h
Vrd=16km/h
Photovoltaic cells are the most efficient means of converting solar energy to electricity. Option b is correct.
<h3>What is a cell?</h3>
A cell is a voltage and current-producing device that consists of a single anode and cathode separated by an electrolyte.
One or more cells can make up a battery. One cell, for example, is one AA battery.
Light intensity on a solar cell is often measured in "suns," with one sun roughly equivalent to 1 kW/m².
Concentrated sunlight improves the ratio of current generated while the device is lighted vs when it is dark, hence enhancing output voltage and efficiency.
Photovoltaic cells are the most efficient means of converting solar energy to electricity.
Hence, option b is correct.
To learn more about the cell refer to:
brainly.com/question/3142913
#SPJ1
Answer:
Yes it is
Explanation:
the sum moles at the left side equals the sum of moles at the right side
When the magnets are released and begin to move, the magnetic force changes potential energy into kinetic energy;<u> option D</u>
<h3>What is magnetic force?</h3>
Magnetic force can be defined as the force of attraction or repulsion that is felt or produced between the magnetic poles and electrically charged moving particles.
Magnetic force is the force that exists due to the attractio or repulsion of objects place around the region of space where a maget exerts its force.
When a magnet is released ai a system of magnets and allowed to move it increases the kinetic eergy of the system by converting potential energy to kinetic energy.
Learn more about magnetic force at: brainly.com/question/28989998
#SPJ1
