apply ohms law to obtain the relationship for combined resistance when three resistors R1, R2,R3 are connected in a) series b) parallel

Dear Student ,
Here is a link given below which will definitely help you to get the answer of this question with proper explanation .
https://www.meritnation.com/cbse/class10/studymaterial/science/science/electricity/10_156_8690#slide1_series-and-parallel-circuits

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