Question:
(a) Three resistors 2 Ω, 4 Ω and 5 Ω are combined in parallel. What is the total resistance of the combination?

(b) If the combination is connected to a battery of emf 20 V and negligible internal resistance, determine the current through each resistor, and the total current drawn from the battery.

Answer:

(a) There are three resistors of resistances,

R₁ = 2 Ω, R₂ = 4 Ω, and R₃ = 5 Ω

They are connected in parallel. Hence, total resistance (R) of the combination is given by,

Therefore, total resistance of the combination is .

(b) Emf of the battery, V = 20 V

Current (I₁) flowing through resistor R₁ is given by,

Current (I₂) flowing through resistor R₂ is given by,

Current (I₃) flowing through resistor R₃is given by,

Total current, I = I₁+ I₂+ I₃ = 10 + 5 + 4 = 19 A

Therefore, the current through each resister is 10 A, 5 A, and 4 A respectively and the total current is 19 A.

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