a.Three resistors `2Omega,4Omega` and 5`Omega` are combined in parallel. What is the total resis- tance 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.

Explanation

a.`(1)/("R")=(1)/(2)+(1)/(4)+(1)/(5)=(10+5+4)/(20)=(19)/(20)" "thereforeR=(20)/(19)Omega`
b.Current through`2Omega=(20)/(2)=10A`
Current through `4Omega=(20)/(4)=5A" "`Current through `5Omega=(20)/(5)=4A`
Hence total current,I=10+5+4=19A
`I=(E)/(R)=(20)/((20)/(19))=19A`