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:A
Explanation:
Engines in car are 4 stroke engine . A 4-stroke engine is internal combustion engine which derives its power by four piston strokes . Internal combustion means combustion takes inside the engine i.e. is in cylinder.
There are process in 4 stroke engine
- Intake: Intake of air
- Compression:compression of intake air to a high pressure
- Combustion:Fuel is injected and burned to get power
- Exhaust:removal of exhaust gases after combustion
Ionic bonds are formed between a cation (metal) and an anion (nonmetal)