It will take the battery 15 hours to discharge completely.
<h3>Energy stored in a battery</h3>
Energy is defined as the ability or capacity to work. The formula for calculating the energy stored in a battery is expressed as;
Energy stored=Power×Time
Energy stored = ΔV * t
where
ΔV is the change in velocity
t is the time
Substitute
Energy stored = 12.0 * 90.0
Energy stored = 1080 W.h
Total power consumed by the headlight = 2 * 36
Total power consumed by the headlight = 72Watts
Determine the time it takes to dischage
Time = Energy Stored/Power
Time = 1080/72
Time = 15hrs
Hence it will take the battery 15 hours to discharge completely.
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Answer:
B. After a photon of light is absorbed by certain metals, electrons are found to be ejected from the metals. This is because the energy contained in the massless photon is used to eject an electron with mass out of the metal.
Explanation:
Before, in the early days, it was proposed to form a combined theory by joining the theory of conservation of mass and the theory of conservation of energy and form a combined theory of conservation of mass-energy. It was done to explain a particular theory of 
.
The is the emission of the electrons form the surface of a metal when light energy strikes on it. Here, in this phenomenon, both mass and energy is conserved.
When the light strikes a metal surface, electrons gets ejected from the surface. The energy of the photon is used to eject the electron form the metal surface.
Your answer for this question is the third option.
