In series circuit, Req = R₁ + R₂ + R₃ + ···
In parallel circuit, 
<h3>Q7.</h3>
total resistance in the upper branch = R₂ + R₃ = R₂ + 2


R₂ + 2 = 12
R₂ = 10Ω
<h3>Q8.</h3>


Req = 1.7Ω
Answer:
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A graph of real speed can have a section that's as steep as you want,
but it can never be a perfectly vertical section.
Any vertical line on a graph, even it it's only a tiny tiny section, means
that at that moment in time, the speed had many different values.
It also means that the speed took no time to change from one value to
another, and THAT would mean infinite acceleration.
86.4×10^6 joule is energy does one house use during each 24 hr day.
20 MJ of light energy
Consumption of electricity is 1 kW.
The energy consumption lasts for 24 hours.
energy=power×time
energy=10^3×24×3600
energy=86.4×10^6 joule
Energy in physics is the ability to perform work. Different shapes, such as potential, kinetic, thermal, electrical, chemical, radioactive, etc., may be assumed by it. Other examples of energy being transferred from one body to another include heat and work. Energy is always distributed after it has been transported in accordance with its type. Thus, heat transfer could result in thermal energy, whereas work could result in mechanical energy.
Motion is a trait shared by all forms of energy. For instance, if a body is moving, it has kinetic energy. Due to the object's design, which incorporates potential energy, a tensioned object, like a spring or bow, has the ability to move even when at rest.
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Answer:
law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time.